Acts of Stupidity by Character

Many of the deaths that occur in Happy Tree Friends are a result of the main characters doing something ignorant, unwise, or just downright stupid. Almost every character is prone to committing these actions, causing the deaths of themselves and/or others around them.

Cuddles
Cuddles is known for being mischievous and self-centered, which is often the root cause for several of his actions.
 * Water You Wading For: Cuddles jumps into a lake despite the fact that swimming is not allowed, which Flaky points out. Because of this, Cuddles is attacked and killed by the creatures in the lake.
 * Sweet Ride: He does not look where he is skating, causing him to crash into a staircase.
 * Flippin' Burgers: When Fliqpy sticks a straw into his chest his blood spurts out of the straw, so he drinks his own blood thinking it would help, then dies/passes out from massive blood loss. (Debatable, because he couldn't think of any other way to save himself.)
 * Let It Slide: Oblivious that a water valve was turned off, Cuddles pushes Flaky down a dry slide, skinning her and loosening all the bolts on a section of the slide.
 * Can't Stop Coffin: He climbs over a fence without seeing what is on the other side (in this case, a deep hole where he gets trapped in a coffin, burned, drowned, and subsequently killed).
 * A Change of Heart: He plays soccer with Handy's heart.
 * Dunce Upon a Time: He chooses a hiding spot where he is standing on blades designed to finely grind. He also visibly and audibly moves in this hiding spot, giving away his location to Giant Lumpy (to be fair, he was hiding in a pepper grinder, and he could not help sneezing).
 * Aw, Shucks!: He drives past a boom gate that, although malfunctioning, was clearly trying to go down, indicating that a train was coming.
 * Hear Today, Gone Tomorrow: In the opening scene, despite being a rabbit, he holds the tin can phone to the side of his head where a human ear would go instead of up at the base of his ears. This could likely be the real reason he could not hear Lumpy.
 * YouTube 101: Subscriptions: He believes that Giggles was actually on a date with Disco Bear despite her obvious hatred of the bear. (To be fair, this was mostly Disco Bear's fault.)
 * Breaking Wind: He stands outside in plain sight, not making any effort to protect himself from a tornado.
 * You're Kraken Me Up: He does not see the tentacle controlling Giggles, even cheering when Lumpy "saves" her.
 * TV series Volume 1  (cover): He sticks a fork in an electrical outlet and is electrocuted; his eye popped out and he may have died.
 * TV Series Volume 3 (cover): He lets The Mole cut his hair, resulting in his head being chopped off.

Giggles
Like most characters, Giggles is blissfully ignorant and unaware of hazards until the last minute. She does seem to be narrowly smarter than the other characters, at least in common sense.
 * Eyes Cold Lemonade: She sets Petunia's eye juice to sell or drink later, even after tasting it.
 * Better Off Bread: She skips through flowers until, not watching where she was going, she falls off a cliff. (Debatable, as the cliff might not have been visible against all those flowers).
 * Kringle Tree: While mostly on Lumpy's accord, Giggles unwisely stood in the spot where Lumpy was about to swing his axe.
 * Cold Hearted: Tries to kiss Cro-Marmot, despite having her lips ripped off when she kissed him in Wipe Out.
 * Kringle Karols: Even though she is surrounded by snow, she continues to scream in pain after her candle lights her on fire.
 * Every Litter Bit Hurts: She puts a wooden hair brush in a plastic recycling bin. (However, she did not have a trash bin.) She also entrusts The Mole with a litter-picker despite his blindness.
 * A Change of Heart: She hands Lumpy the scalpel to perform the operation without telling him that Disco Bear wasn't given anesthesia.
 * Something Fishy: After Russell's Piranha jumps into her cup of water, Giggles drinks it without looking inside first. Thus the piranha chews her to death. (Debatable, because how many times do people really look in their drinks?)
 * Breaking Wind: She stands out in the open while a tornado is coming, making no effort to get to a safer spot.

Toothy
Toothy tends to act on impulse, in terms that he chooses not to think before doing things.
 * Nuttin' but the Tooth: While performing dentistry on Nutty, he reads a book on how to perform the operation the whole time instead of actually reading it beforehand, and then pierces a needle all the way through Nutty's cheeks so that none of the Novocain even enters him. Then he makes a hole through the back of Nutty's head using a power drill. After that, he tries to remove a loose tooth by tying a string to it, removing Nutty's lower jaw in the process.
 * Eye Candy: Runs across a path while holding a lollipop while his eyes are closed.
 * Class Act: As he flees in terror, he tosses a lit candle near a stage curtain, creating a fire that burns down the school. (Debatable, as it was a reaction)
 * From A to Zoo: He doesn't hesitate or panic when he should have been able to see the rhino charging at his direction, instead he stays perfectly still.
 * Who's to Flame?: He tries breaking the door down with an axe, but throws the axe at the door instead of repeatedly swinging at it.
 * Mime to Five: Rather than the recommended two spoonfuls, Toothy pours two whole barrels of gunpowder into a cannon. This leads to an explosion that kills Toothy and splits Cuddles in half. (Debatable, as Mime did not give very good instructions)
 * Cold Hearted: He tosses a snowball at Giggles just as she was about to kiss Cro-Marmot. This leads to Giggles' eyeballs getting stuck to the ice, forcing her to pull them out. (Debatable, as this could be a prank.)
 * Brake the Cycle: He rides his bike despite the fact a bolt is missing (which he clearly knew was missing), leading it to fall apart and gradually killing him.
 * His Smoochie: He eats a rotten Easter egg with little thought, poisoning himself seconds later.
 * Kringle Karols: He attempts CPR on Cuddles by pressing on his stomach or even pelvis instead of his chest. Also considering the damage, even correct CPR would do nothing.
 * Better Off Bread: He is oblivious to the fact that Giggles is dead when Splendid puts her down and witnesses a shower of meteorites without making any effort to run for shelter, resulting in his death.
 * Can't Stop Coffin: He, along with Cro-Marmot and Russell, fails to notice Cuddles' absence when he goes to retrieve the baseball, and should have been aware of the long amount of time it took Cuddles to retrieve it.
 * Peas in a Pod: He stands perfectly still when a Pod Lumpy is about to cut him with an axe.

Lumpy
Lumpy is considered by most fans as the least intelligent character in the series and is responsible for the majority of the stupid acts committed in the show. However, on closer examination, this may not be the case.
 * Spin Fun Knowin' Ya: He spins the merry-go-round so hard it causes Cuddles, Toothy, and Giggles to fly off (to be fair, they did keep tell him to spin it faster).
 * Wheelin' and Dealin': He wears a snorkel and scuba mask in a car race.
 * Pitchin' Impossible : He gives The Mole some balls to pitch with despite the fact that he figured out he is blind.
 * Treasure Those Idol Moments: He hits Flaky with his car in clear sight while she was in a playground. He also seemes completly unfazed by the fact that he just killed another character.
 * You're Bakin' Me Crazy: He brings Petunia a blood-covered cake and says "Merry Christmas!" at her birthday party.
 * Meat Me for Lunch: He does not seem to care at all that Lifty & Shifty were killed, and uses their remains to make meat for his butcher's shop (Debatable; Lumpy not caring that the raccoons were killed and feeding them to his customers could simply have showed his vengeful side. However, he looks surprised when Petunia realizes she was eating someone.)
 * It's a Snap: He falls for bear traps baited with cheese.
 * Snow What? That's What!: He lies shirtless on a hammock with a drink in the winter. (Debatable, as he seemed completely unaffected by the cold just like real moose and might have just been embracing it.)
 * Happy Trails Pt. 1: He is not paying attention to the road (even walking away from the wheel), causing the bus to crash onto a desert island. (Debatable; Petunia and Mime took his attention away from the road.) He never thinks about hitting the brakes.
 * Class Act: He instructs Toothy to go on with his act despite the other play actors' injuries (possibly done out of apathy, not stupidity). He also casts Nutty in a play that has a character dressed as a candy cane. (Debatable; it is unknown if anyone knew about Nutty's addiction at this time).
 * Rink Hijinks: He wears skis instead of skates at a roller skating rink (to be fair, possibly for balance) while wearing boxers.
 * The Way You Make Me Wheel: He shaves while driving, resulting in his death, and Handy's death as well.
 * I Get a Trick Out of You: He unintentionally suffocates a bird by keeping it in his hat for too long, saws Cuddles in half due to a magic trick, and later uses up the blood which Cuddles needed to survive.
 * Let It Slide: He wears Flaky's skin as a hoodie, not only not noticing (or ignoring) the fact that it is Flaky's skin but completely neglecting to cover his lower half, which is what the problem is.
 * Icy You: He somehow gets his tongue stuck in hot dog rollers and keeps working with his tongue stuck.
 * Out on a Limb: He cuts off the leg which was not stuck under the tree instead of vice versa.
 * Remains to be Seen: He chooses a leaf blower over a chainsaw to kill the zombies. (Debatable, because Lumpy successfully defeated Flippy with said leaf blower, it really is not stupid at all. But, considering the situation and Lumpy's luck, the chainsaw would have been a better choice. Though also given Lumpy's luck, he would likely have cut off his own limbs with the chainsaw and even if he did not, it would have taken much longer to defeat all of the zombies.)
 * From A to Zoo: He puts in a dart the wrong direction, causing it to go down his throat and tranquilizes himself (to be fair, he may have been panicked and had no time to realize this error). He also does not notice a rhino's horn obviously went through Toothy's head, and mistakes a baboon for Sniffles.
 * The Wrong Side of the Tracks: He designs a roller coaster so poorly that it causes the deaths of the riders and himself. He also nails a wooden board to his ride with Mime impaled to it.
 * Doggone It: Even though he already figured out that whistling sets Whistle off, he whistles with his own mouth after he gets the whistle out of his throat, also giving away his hiding spot.
 * Don't Yank My Chain: He falls for Lifty & Shifty's bad disguises and arrests Handy and The Mole. He leaves the cell open with the keys near it. He takes several seconds to realize that Handy and The Mole have gotten away. He uses part of The Mole's sweater (a clue to finding them) to blow his nose.
 * Dunce Upon a Time: He sticks a fork into a plugged in toaster three times in order to get Flaky out.
 * Concrete Solution: He looks inside a nail gun and fires it. Then he uses a bag of sugar instead of cement to build a bridge.
 * Wishy Washy: He walked in with his shoes dirty, then exited and came back in only to realize that there is a mat underneath him. When Petunia chokes on a glove, he puts his plunger into her mouth in order to help her. (Debatable because between the extreme issues with Petunia's pipes and her now choking, he was in a state of panic and tried to act very quickly on impulse.)
 * Who's to Flame?: He plays with a lit match, which is ironic considering his fireman job (Debatable; he is playing in such a way that will not cause disasters. However, playing with fire at all is dangerous).
 * As You Wish: He sets Cub on fire and gets him run over by a fire truck (Debatable; it really depends on how Pop worded his wish - which seems to have been for a "hot ride" - as Lumpy was able to successfully grant Nutty, Disco Bear and Sniffles' wishes.)
 * Take a Hike: He uses up all of the drinking water for shaving instead of using the water that was in the lake. He does not pay enough attention to the group. He takes a nearly broken bridge over a strong one. (Debatable, as this was out of fear, so he was not paying attention or did not notice). He repeatdly douses Sniffles under water when only one splash would've been enough to put the fire out.
 * A Change of Heart: He repeatedly loses the normal-sized hearts due to lack of attention.
 * Blast from the Past: He repeats his act from Spin Fun Knowin' Ya.
 * Idol Curiosity: He mistakes ice in Toothy's drink for an iceberg. (However, he was looking through a telescope, and the image he saw gave a wrong impression.)
 * Home Is Where the Hurt Is: He folds the blueprints of Giggles' new house into an origami crane. (Debatable; he may have just done this selfishly, looking for a replacement for his broken one). Later, he connects electrical pipes to normal pipes for the shower, which electrocutes Petunia later.
 * Aw, Shucks!: He unintentionally destroys his house while trying to kill a crow, and mistakes Toothy's corpse for his scarecrow.
 * Wingin' It: He uses many electronics, despite Mime telling him not too. Later, he takes all five parachutes, and then fails to properly wear even one of them.
 * Tongue in Cheek: He mistakes the skin from Sniffles' hand for a glove (even though he already has his glove and only one is required to play golf) and his organs as a mini-golf course.
 * I've Got You Under My Skin: He pokes the tip of the laser to Sniffles' invention causing him to be electrocuted. He tries to stop Sniffles from traveling further up his body, but ends up severing his leg. (Debatable; this was a weird and unexpected result to a somewhat logical attempt.) He is also shown to have numerous strange items, including a plane propeller and a bear trap, inside his pockets (possibly for the numerous jobs that he has).
 * Junk in the Trunk: He takes forever to compare the elephant in Lifty & Shifty's car and the one he put on his missing elephant poster. He also chooses a pogo stick over a race car to chase after the thieves. (Debatable, as the pogo stick offered more versatility).
 * Hear Today, Gone Tomorrow: He does not realize that his can is on his butt and runs to get some new things. He later tries to use a trombone as a hearing aid, tries to phone the hospital while deaf, wears a birthday hat the wrong way (Debatable, as it was likely simply a difficult task to get it around his antlers), and tries to phone for help using a can telephone.
 * Double Whammy Part I and Part II: He shows Flippy ink blobs that even to a normal person look like a dagger, a bomb, and an explosion, causing him to flip out. (Debatable, as this could have been done as a way to test what causes him to flip out.) He later hypnotizes himself, making him act like a chicken. This is later seen in part II, where he is inside a chicken truck trying to lay eggs.
 * Can't Stop Coffin: He buries what was originally an empty coffin, fills the hole with water, and leaves his truck in reverse, driving it into the grave and crushing Cuddles.
 * All Flocked Up: He tries to pop his balloons with a rock, but accidentally throws it at Toothy, causing his face to land in hot tar (Debatable, as this may simply be bad aim).
 * Something Fishy: He mistakes the bowl for Russell's Piranha for a helmet and puts it over Russell's head.
 * I Nub You: He sews Handy and Petunia together, and ends up sewing his own arms on them. (Debatable, as he likely was just missing body parts and was really just trying to find a way to keep them both alive, that being the only option).
 * See You Later, Elevator: He tries to use an elevator during a fire, which is not safe. He tries CPR on the lower half of Cuddles' corpse and uses too much pressure, causing the corpse to explode.
 * Milk Pong: He chokes on a ball, later drinks bleach instead of milk, does not notice a rat in his cup (twice) (Debatable, as like with Giggles, who really looks into their drinks?), and tries to get a ball out of a wood chipper with his bare hands.
 * The Chokes on You: He eats doughnuts while working (Debatable; this could be considered more lazy or selfish).
 * Brake the Cycle: He spills too much gasoline while pouring it into his motorbike, which causes him to burn to death.
 * All In Vein: He leaves Giggles in the fridge for too long, causing her blood to harden. (Debatable, because who has not done this with food items?). He later drinks too much blood, causing him to go overweight and preventing him from flying.
 * No Time Like the Present: He brings Handy a pair of mittens, ironic considering his lack of hands. (Debatable; he might not have even been the one to wrap or choose the gift, or it was a mix-up).
 * You're Kraken Me Up: Instead of rescuing Russell, he saves the squid tentacle with Giggles' head on it, thinking it was Giggles. He makes a similar mistake later on by feeding a bottle of milk to Cub's head attached to a tentacle.
 * All Work and No Play: He attempts to save Nutty by jack-hammering the top of the wall, resulting in Nutty's torso getting completely mangled. He later saves Sniffles but is distracted by Lammy, resulting in Sniffles getting smashed to pieces by the excavator's buckets closing in on his head.
 * Pet Peeve: Feeds the birds birdseed despite this previously causing him to be mauled by them.
 * A Vicious Cycle: He eats chips out of Disco Bear's brain. (Debatable, as he seems to be completely aware of doing so.) While hiding from a possessed tricycle, he bites a chip, and the crunch noise blows his cover.
 * Dream Job: He messes with the television so much that Sniffles' dreams become erased and the TV turns off. (Debatable; he likely had no idea what he was doing. However, he should have recognized Sniffles on the TV). After the TV shuts down, he throws Sniffles' TV remote, which isn't his, on the ground and leaves the room without ever doing what he came to do in the first place, cleaning Sniffles' room.
 * Ski Patrol: He messes up and causes the deaths of numerous characters. (To be fair, this was mostly the narrator's fault for misinterpreting the instructions, and the fact that the narrator continues to praise him even after such mishaps).
 * Kringle Tree: He smashes Giggles' head trying to chop down a tree with an axe. (On a side note, Giggles was standing in the way.)
 * Kringle Feast: It takes him a long time just to start up a lighter. Then he kills himself (and others) from an explosion because he left the gas open too long while trying to light a lighter. (Debatable because to be fair, having a hard time starting a lighter is not by itself a sign of stupidity).
 * Kringle Frosty: He skis over Sniffles and Toothy, killing them. (Debatable; he might have missed them because he plowed through their snowman, blinding his vision).
 * Strain Kringle: He throws a rock at Cuddles and Toothy when a snowball would have been more preferable. (Debatable; he could have just done this for the sake of being a jerk.)
 * Seize the Day: He uses a defibrillator on Cuddles while he is having a seizure, resulting in his death.
 * Happy New Year: He crashes into Flaky and Russell, crushes Cuddles, and somehow gets film wrapped around his body. (To be fair, though, he was in a rush.)
 * Moppin Up: He forgets (or neglects) to put a Wet Floor sign up while mopping, causing Sniffles to break his head. (Debatable; he was currently in the process of mopping, so the sign shouldn't have been necessary, and considering that Sniffles did not notice Lumpy mopping, he certainly would not have noticed the sign).
 * Volume 2: Second Serving (cover): He can be seen sticking a butter knife into a toaster.

Petunia
Petunia commonly makes mistakes, mostly caused by her OCD. However, she appears to be very unintelligent, making mistakes comparable to Lumpy on many separate occasions.
 * Wishy Washy: She washes her hands without using soap and only puts her hands in the sink for a few seconds. She keeps a mat that guests are suppose to wipe their feet on inside her house instead of outside. She also downs a whole bottle of mouthwash, an act that could have killed her. She later attempts to breathe in a glove. After getting increasingly dirty trying to get clean, Petunia resorts to skinning herself alive using a potato peeler. (Debatable, as she lost her stability from seeing Lumpy's corpse and because of her severe obsessive-compulsive disorder (OCD).)
 * A Hole Lotta Love: She does not pay attention while driving and nearly runs over Mime.
 * Breaking Wind: Probably her most well-known blunder, she strikes a match in the middle of a gas cloud induced by Splendid. As a result, the earth is set aflame and kills presumably billions.
 * Who's to Flame?: She leans on a burning stove while talking on the phone, resulting in her tail burning. (Debatable, as she was not paying attention, though this could be considered stupid in itself.)
 * Peas in a Pod: She takes a very long amount of time to figure out that she had lost an arm. Later, she just stands there screaming rather than attempting to run away.
 * Wingin' It: She does not take off her air freshener when cleaning the toilet or using the sink.
 * Home Is Where the Hurt Is: She trusts Lumpy with pipes.
 * Royal Flush: She sticks her eye up her hoover.
 * My Better Half: Judging by the angle she is in, she could have warned Handy to jump out of the boat before he died. Instead of jumping out of the boat, Petunia just screams and lets herself get sliced in half.
 * Camp Pokeneyeout: She pulls a slingshot with grape juice covering her hand, making it too slippery and killing her.
 * Take a Hike: She drinks contaminated water when she could have ran back to the lake. (To be fair, she was dehydrated.)
 * Pitchin' Impossible: When The Mole's pitching goes wrong, she simply stares rather than moving out of the way.
 * Flippin' Burgers: When Fliqpy goes over to the grill, she merely stares at him confused rather than taking some sort of action.
 * I Nub You: She and Handy use their bodies as bowling balls, resulting in them being crushed by pinsetters.
 * Happy Tree Friends: False Alarm (episode): She rides her bike in the middle of the road, which is both illegal and unsafe, leading to her death.
 * You're Kraken Me Up: Sits right underneath Lumpy's lifeguard chair.
 * Dream Job: She does not know the cause of Sniffles' traumatizing experience, and carts him over to the television. (Debatable.)

Handy
Handy does not make as many mistakes as others. In fact, he is one of the most intelligent characters, though even he has his moments.
 * Home Is Where the Hurt Is: He may have invited Lumpy to build Giggles' home. (Debatable, as Lumpy was not involved in the discussion on what to do, so he may have been there by chance.)
 * Who's to Flame?: He drops what he thinks is water on the sidewalk, killing three characters in the process, instead of doing it over a burning house.
 * Don't Yank My Chain: He trusts Mole to use a mallet to hit a chisel Handy is holding between his teeth. He could also have looked for someone working at the sawmill to remove his chains. Instead, he attempts to cut off the chains using a train. (Debatable, as he may have looked off screen and found no one and, in real life a train would've broken the chain instead of dragging it.)
 * Shard at Work: He fails to notice where he is walking, resulting in him stepping on a glass shard.
 * I Nub You: He and Petunia use their bodies as bowling balls, which is unsafe, resulting in them being crushed by pinsetters.
 * Pet Peeve: He walks in the middle of the street with his eyes closed, which results in him getting stuck in a hole left by the blob. (Even if he didn't fall in the hole left by the blob's slime, he would likely have ended up dying the same way he did later in the episode.)

Sniffles
Despite being considered one of the most intelligent characters in the series by most, Sniffles has made many illogical mistakes. Some derive from his complicated inventions, which are plagued with oversights Sniffles does not notice until it is too late. To be fair, many of his mistakes double as stupidity AND intelligence.
 * Spare Me: He attempts to toss a bowling ball using his snout, leading to his head being torn off.
 * Tongue Twister Trouble: He uses his tongue to catch an ant on ice; it would have stuck to the ice even if the ant had not moved.
 * Happy Trails Pt. 2: Jumping the Shark: He designs a rocket so strong it can go all the way to the sun and cannot be diverted from this course.
 * Suck It Up: He gives his invention a flexible nozzle, which can get stuck to the side of his head with the other side still attached to his face. He also does not try to remove it from his face at any point during the torture session.
 * His Smoochie: Since he invented the growth serum, he should have known its effects and not have drank it. Rather, he should have poured it on his body if he wanted to grow himself.
 * Party Animal: He does run away after Toothy is killed, but it is unknown what he was doing during Cuddles, Nutty, and Mime's deaths. He had plenty of time to leave the house. He uses a barrel filled with water as a hiding spot, almost causing him to drown, instead of simply running out of the house.
 * Who's to Flame?: He uses a wood ladder to get to the window of a house when the fire clearly makes it too dangerous to do so.
 * Every Litter Bit Hurts: He just watches as The Mole stabs his foot with a litter pick, not making any attempt to move his foot. (To be fair, Mole stabbed it quite quickly.)
 * Take a Hike: He runs around randomly while on fire instead of stopping, dropping, and rolling on the ground or heading for the lake.
 * A Hole Lotta Love: He lets the Mole make and lead with the map. He designs a lookout post that is not shatter-proof, causing Mole's head to burst.
 * Dunce Upon a Time: He visibly and audibly moves in his hiding spot, giving his location away to Giant Lumpy.
 * Blast from the Past: After dropping a glass of milk, Sniffles decides to build a time machine rather than cleaning up the mess and replacing the glass of milk. In doing so, he creates various time anomalies. After catching Cuddles in a plane, he turns all the way around to check on Cuddles while still flying the plane. He also should not have landed the plane in the park.
 * Concrete Solution: Carrying Nutty in an ambulance, Sniffles forgets to strap down his patient's gurney. He finally attempts to do so while still driving his vehicle, causing a crash as well as his death.
 * Mime to Five: He goes in water too deep for him to touch the bottom.
 * Idol Curiosity: He keeps carrying the idol with him despite seeing all the disaster it is causing. Later, he tries to stop an earthquake by barricading the door and throwing stuff in it.
 * In a Jam: He shoves cymbals in Handy's mouth when he was having a seizure, leading to his death. (Debatable, because Sniffles placed the cymbals in Handy's mouth to prevent him from biting his tongue off). With his medical experience, Sniffles should have known that he was supposed to take away Handy's hammer and screwdriver so he does not get hurt from them, turn off the strobe lights, and wait it out.
 * A Sight for Sore Eyes: When he sees something coming his way but cannot tell what it is, he stands in the way and tries to figure out what it is instead of moving out of the way.
 * Wingin' It: Similar to Blast From the Past, being the only pilot operating a plane, it is rather unwise of him to encounter Lumpy personally. He could has simply spoken to Lumpy via speaker.
 * Tongue in Cheek: Even after being painfully tortured once in the episode, Sniffles' determination to eat the Ants consumes him, and he tries to use a mind-control helmet and robot to do the job. The Ants once again get the upper hand and kill him in a gruesome, agonizing way. This happens in other episodes, but the show's lack of continuity is not here to justify it.
 * I've Got You Under My Skin: He faces away from the door for no real reason while waiting for Giggles to answer, so if she was inside, she would have just been staring at his back. Despite staring right at her (unlike Lumpy, who was understandably focused on the door), he takes a long while to to realize he's looking at Giggles buried in the snow. Considering his intelligence, Sniffles could have helped Giggles by taking her to a hospital. Instead he uses a shrinking submarine that comes with a timer indicating how long he will stay microscopic (which he could have turned back to keep himself that size until the job was done, which he never does). He flew right through Lumpy's optic nerve instead of around it. Also, when he climbs out of the machine, he steps on the timer, shrinking it on himself. Lastly, he crawls for a first-aid kit for help, despite how incredibly severe his injury was.
 * Wrath of Con: He doesn't try to sneak past the blind security guard. He keeps his ticket in his pocket when it is supposed to be around his neck and forgets it is there. He asks Splendid for an autograph while Splendid was busy holding up a chunk of debris. To be fair, this could also count as part of Splendid's accord.
 * Happy Tree Friends: False Alarm (episode): He either gives or lets Nutty take a chainsaw into his padded cell (Debatable; he may not have done that and it could have been for psychological examination).
 * Peas in a Pod: He blatantly walks right into a Pod Lumpy and, as the Blurb points out, he would have walked into the wall if the Pod Lumpy was not there.
 * Something Fishy: He puts his hamster right next to Russell's piranha (Debatable). He also does not even notice the fishbowl on Russell's head instead of the helmet.
 * Random Acts of Silence: Despite there not being an emergency, he and Nutty try to sneak out the fire exit. Furthermore, when the alarm goes off they do not even exit, but instead stand there and stare.
 * All Work and No Play: Sniffles, along with Lammy and Nutty, decide to play on a playground that is clearly under demolition. In particular, Sniffles goes down a slide despite it having holes in it, causing his body to be grated like cheese and slide right into wet cement.
 * Buns of Steal: He rides his bike in the middle of the road, which is both unsafe and illegal, leading to his death.
 * Pet Peeve: He brings the Blob out in public and lets it hump Lumpy's leg, despite knowing the danger. Then he walks the blob in the middle of street. Finally, similar to Concrete Solution, Sniffles does something without stopping the car first. In this case, checking on his pet after it makes a hole through the floor. This sends the vehicle into a sidewalk where his head is sliced off.
 * Dream Job: He designs his dream machine in a way that makes it was possible for someone else (case in point, Lumpy) to change his dreams by simply flipping through channels with a TV remote.
 * Moppin Up: With a big puddle visible on the floor (and Lumpy in the process of mopping it), Sniffles should have watched where he was going or walked more carefully.

Nutty
Nutty has done many things that endanger his and others' lives, mostly because of his candy addiction and the fact that he always acts before he thinks.
 * Class Act: Nutty bites a chunk off Sniffles' body, who was dressed in a candy cane costume, causing the play to spiral out of control.
 * Stealing the Spotlight: Seeing a string of Christmas lights as candy, Nutty swallows them and gets disemboweled by Lumpy as a result.
 * Concrete Solution: Hanging onto the edge of a bridge for dear life, Nutty begins eating it after realizing it is made of sugar. It comes to the point where he bites off the one last bit of the bridge holding two halves together, leading him to be violently ripped in two.
 * Chew Said a Mouthful: He fractures his jaw trying to bite a jawbreaker, cuts his braces loose, puts a jawbreaker in a blender, and causes several deaths (including his own) in an attempt to get the confection back.
 * Wipe Out: After dropping his ice cream into a tidal pool, he mistakenly puts a sea urchin into his cone and bites into it.
 * A Sucker for Love: Upon bashing a gumball machine open, Nutty places a handful of gumballs into his mouth, along with shards of glass. He gets his teeth and gums cut, followed by his face when he blows a gum bubble.
 * Random Acts of Silence: Despite there not being an emergency, he and Sniffles try to sneak out the fire exit. Furthermore, when the alarm goes off they do not even exit, but instead stand there and stare. Later, when Sniffles is killed, he just panics rather than running off.
 * All Work and No Play: Nutty, along with Lammy and Sniffles, decide to play on a playground that is clearly still under demolition. In particular, Nutty rides on a swing-set located dangerously close to a bunch of large nails, causing him to get impaled on them.

Pop
Almost earning a reputation similar to that of Lumpy, Pop's stupidity derives from his incompetent parenting, usually the cause of most of Cub's deaths and injuries.
 * Snip Snip Hooray!: He accidentally cuts off one of Cub's ears with scissors. Then he leaves Cub unattended with an electric shaver, paying no attention as Cub puts the item in his mouth as he activates it. He is oblivious to Cub's following death.
 * Water Way to Go: He buries Cub in sand from the neck down and leaves him to get ice cream. Cub then gets submerged in high tide and Pop believes his son has been washed out to sea. He brings a boat on the water, running over Cub's head and ultimately shredding him to death with the motor.
 * Stealing the Spotlight: He shoves Cub's tooth through his upper lip instead of back into his gums. (Debatable, because the tooth wouldn't stay in his gums, cruel nonetheless)
 * From Hero to Eternity: He lets Cub play with a bottle of either liquid detergent or bleach.
 * And the Kitchen Sink: He sends Cub rolling down a hill in a wagon, goes through a garden of cacti instead of around it, leaves Cub unattended in the sink until his fur is burned off, almost kills Cub by activating the garbage disposal, breaks one of Cub's bones, almost kills him again by using his car, and drowns him by once again leaving him unattended.
 * Every Litter Bit Hurts: He fails to notice Cub choking on litter and mistakes his remains for trash.
 * Read 'em and Weep: Kills Cub after he is turned back to his normal self after The Demon that possessed him was removed by Lumpy.
 * See You Later, Elevator: Pop tosses a lit match out a window, which gets blown into the lower floor and creates a fire.
 * Clause For Concern: In a post-credits scene, Pop crushes Cub by closing a door on him. (Debatable, because he did not know Cub was right behind the door.) He also tries to put the presents in the boot of the car without trying to shove them in and eventually drives with the presents mostly sticking out.
 * Bottled Up Inside: Stops in the middle of a crosswalk to pick up a coin, allowing Cub and much of the stroller to be hit by Russell's car, to which he remains completely oblivious. He is also oblivious that his water container has Russell's corpse in it, and fills a cup with his blood.
 * Concrete Solution: Pop can be seen driving through the damage of the destroyed bridge, but he completely fails to look at all the damage and destruction around him. He is also oblivious that Cub was crushed by Nutty's concrete stomach, and mistakes the stomach as Cub because it wore Cub's beanie.
 * Cubtron Z: Encourages Cubtron (who is much bigger than him) to sit on his lap.

Cub
Cub's stupidity is generally excusable, since he is very young and is naïve about the concept of death. Occasionally, there are exceptions.
 * Snip Snip Hooray!: He sucks on a razor despite knowing what it did to his head. (Debatable, as he did not feel pain the first time.)
 * Cubtron Z: After being reincarnated into a giant robot, he uses Cuddles, Giggles, and Petunia as crayons to draw on a building.

Flaky
In contrast to the blissful ignorance of most characters, Flaky is known for being very cautious about her surroundings; thus she can be considered as one of the wiser characters. But even she has made mistakes.
 * Water You Wading For: She tries to save Cuddles with a stick that does not reach even remotely close enough to him. Later, she throws a lifesaver to his remains.
 * Happy Trails Pt. 2: Jumping the Shark: She forgets that she is in an inflatable life raft, and leans back and pops it.
 * Let It Slide: Considering her fear of water, it is odd for her to even go to a water park in the first place. (Debatable ​as Cuddles likely could have dragged her there)
 * Party Animal: She stands on the top part of a ladder where it warns you not to and does so with no one stabilizing it, both of which are extremely dangerous.
 * Dunce Upon a Time: She chooses a toaster as her hiding spot, setting the likelihood to be either intentionally or accidentally burned to death. She also visibly and audibly moves in this hiding spot, giving away her location to Giant Lumpy.
 * A Change of Heart: She plays goalie during a soccer game, despite her being afraid of objects flying towards her. (Debatable, as she may have wanted to play soccer but all of the other spots on the team were taken. But then again she appeared to be afraid of the ball.)
 * Wipe Out: As in Let It Slide, it is hard to imagine why she entered the surfing contest in the first place. Perhaps she wanted to try being brave. Also, she failed to notice that her surfboard was covered in blood or the blood where Handy died.
 * Without a Hitch: She lets her hallucinations distract her from driving, causing her to crash into a pole.
 * The Chokes on You: She somehow does not notice that the "doughnut" she had got was Lumpy's flesh.
 * A Bit of a Pickle: She neglects to drive around the tree blocking the road.
 * Royal Flush: She tries to force a pickle down the toilet with a plunger instead of taking it out when it was clearly too big to go down the pipes even if it was a normal pickle. She also eats it without chewing at all.

The Mole
Some may consider The Mole's actions acceptable since he is blind. However, there are times this rule would not apply.
 * Spare Me: He does not wonder what is blocking the holes in his "bowling ball", instead roughly jamming his fingers right through Sniffles' glasses.
 * Blind Date: He can not tell the difference between a dead Lumpy and Giggles despite many non-visual indicators such as heat, size, and voice before death.
 * Party Animal: In one scene, he can be seen wearing a blindfold despite already lacking eyesight.
 * Who's to Flame?: Fire hydrates do not just flip open like the valve for a gas tank, so he should have questioned that.
 * In a Jam: Despite Cuddles informing him about a mistake (giving a button instead of money), he makes Cuddles donate again. He does not find it weird that a chair was suddenly where his patient laid, and proceeds to sit on Cuddles' corpse.
 * Wipe Out: He shreds Lumpy to death and carves his body into a surfboard. While apparently unable to see, the Mole should have at least heard Lumpy's screams of pain.
 * Autopsy Turvy (Double Whammy Part II): When he cut his foot on the broken glass on the floor, he questions it briefly but just moves on instead of picking up what he cut himself on. (Debatable)
 * Can't Stop Coffin: He somehow does not notice the difference in taste between an apple and an eyeball.

Mime
Mime has caused quite a few of these, with at least one popular case.
 * Mime and Mime Again: He could have simply turned the fan off before Toothy got sliced apart and died.
 * Easy For You to Sleigh: He somehow does not notice Lifty and Shifty are watching him, despite the fact that they are not even hiding.
 * Who's to Flame?: Assuming he can talk, he should do so on the phone instead of mimicing. If he cannot, he should not use the phone in the first place.
 * Dunce Upon a Time: He stays in the broken jar even when about to be stepped on.
 * Mime to Five: He takes a job at a drive-thru window even though he can only mimic talking. His mime instincts once again get in the way when he mimics trying to save an imaginary person drowning, letting Sniffles drown.
 * Something Fishy: He does not even notice the fishbowl is on Russell's head instead of the helmet.

Disco Bear
Disco Bear's intelligence is likely not very high. An early gag consisted of him accidentally killing girls and thinking their suffering was a type of dance move.
 * Stayin' Alive: Disco Bear tosses Giggles into scalding hot tea and Petunia into an electric fence, and obliviously dances to their movements of pain.
 * Who's to Flame?: He drives off in a fire engine with Cuddles still up on the lift. He also activates the fire hose despite the fact that where he was looking, he should have seen that it was attached to the gas tank instead of the fire hydrant.
 * Aw, Shucks!: He is completely unaware that Giggles has been hit by a chunk of popcorn, and believes that the popcorn that hit her is an afro. He then proceeds to kiss her before being killed himself.
 * A Change of Heart: He eats an entire stick of fried butter in one go, leading to a heart attack.
 * Easy Comb, Easy Go: He sticks his head inside a cotton candy machine. He leaves the back of a van open, which causes bottles of hair growth formula to fall out. He sticks his entire head in the formula instead of just pouring it on top. Finally, he cuts off his eyes with a straight razor.
 * Put Your Back Into It: After his spine bursts out of his body, Disco Bear tries to fix it using duct tape, as opposed to calling for an ambulance.

Russell
Russell's intelligence does not seem to be that high. In fact, it could be comparable to Lumpy's at times. However, some of these may be justified due to Russell's vision problems (as seen in A Sight for Sore Eyes).
 * Whose Line Is It Anyway?: He swallows a live puffer fish and it inflates in his throat (to be fair, he was not looking).
 * Snow Place to Go: He tries to ice fish throwing the line from a distance like regular fishing instead of dropping the line right down the hole.
 * Mime to Five: He presumably hires Mime to work the drive thru even though he doesn't talk.
 * In a Jam: He strums an electric guitar while a glass of water lays on top of an audio box. Knocking over the glass, Russell ends up being electrocuted to death.
 * Can't Stop Coffin: He, along with Cro-Marmot and Toothy, fails to notice Cuddles' absence when he goes to retrieve the baseball, and should have been aware of the long amount of time it took Cuddles to retrieve it.
 * Something Fishy: He does not realize that Lumpy put the fish's bowl over his head until it is too late.
 * Bottled Up Inside: After a glass bottle impales his chest, Russell pushes it further into his body just to fit into his car. He does not adjust his seat, preventing the driver's wheel from turning because of the bottle. Also, instead of simply stopping his car and walking to the hospital, he keeps driving forward.
 * You're Kraken Me Up: He is completely oblivious that Giggles' head was torn off and placed on a giant squid's tentacle.
 * Put Your Back Into It: He rips out Disco Bear's spine and head, thinks he has caught a fish, and cooks the remains for a dinner date. It also makes very little sense why he was casting his fishing rod at the beach instead of towards the ocean.

Lifty
Despite being considered by most as pretty much the same character, Lifty seems to have more of the brains of the raccoon duo. However, he still makes mistakes, usually along with Shifty though.
 * Wheelin' and Dealin': He does not notice until the race is about to start that their cart do not have wheels or that it does not have a steering wheel until one is needed, despite having presumably made the cart with Shifty.
 * Meat Me for Lunch: He and Shifty keep a shoe in their fridge.
 * And the Kitchen Sink: He, along with Shifty, notices Pop's car coming in their direction but makes no effort in moving out of the way.
 * Easy For You to Sleigh: He and Shifty try to rob Flippy, despite seeming to know about his mental problems by their uncharacteristic paranoia at first, and their instinct to tie him up. He also blindly trusts the directions out the window without looking for himself which, even if it actually was Shifty giving them, was a bad move.
 * Doggone It: He tries to tug a dollar bill from Shifty's hand instead of letting him focus on driving.
 * Don't Yank My Chain: He and Shifty steal a car that was about to be filled up with gas, and expect to get far with it. They also stay in the car when it is on train tracks even when the boom gates go down.
 * Junk in the Trunk: He holds a mouse in front of Lumpy's Elephant, even though elephants are afraid of mice.

Shifty
Shifty, unlike his brother, seems to have a very low intelligence level, and causes more mistakes than Lifty.
 * Wheelin' and Dealin': He builds a race car without wheels or a steering wheel, and when Lifty asked him where the wheels are responds with "Huh?", seeming like he did not know that cars need wheels.
 * Meat Me for Lunch: He and Lifty keep a shoe in the fridge.
 * Milkin' It: He jumps up and down in hot air balloon, causing him to fall through it.
 * Class Act: After the fire, he is shown trying to drag an injured Lifty to an unknown location by his ears.
 * And the Kitchen Sink: He, along with Lifty, notices Pop's car coming in his direction but makes no effort in moving out of the way.
 * Easy For You to Sleigh: He and Lifty try to rob Flippy, despite seeming to know about his mental problems by their uncharacteristic paranoia at first, and their instinct to tie him up. Also, he alone goes back to retrieve the bag of sand that was there to stop the bear trap from cutting his arm off.
 * Doggone It: He focuses on a tug of war with Lifty over a dollar bill instead of driving.
 * Don't Yank My Chain: He and Lifty steal a car that was about to be filled up with gas, and expect to get far with it. They also stay in the car when it is on train tracks even when the boom gates go down.
 * Swelter Skelter: He tries to return the fire on his hands to the blowtorch, blowing it up.
 * Buns of Steal: He rivets Lifty's foot to their van, presumably in an attempt to save him, when it would have been better for Lifty to jump into Mole's van. Instead of staying in his van, he walks on Lifty's vein just to kick Lifty's head off. He also does not go somewhere else to eat the bun.

Cro-Marmot
Due to his body being encased in ice, Cro-Marmot has made almost no actions, dumb or otherwise. It could be argued that he is intelligent, as he is capable of moving and surfing, among other talents, despite the fact that he is currently frozen.
 * Snow What? That's What!: He throws a snowball at Giggles' corpse.
 * Dino-Sore Days: He bites into the tail of a live dinosaur, thinking it was part of the carcass he was about to dine on.
 * Chill Kringle: He is shown to be attracted to Petunia despite the fact that she is clearly dead.
 * By the Seat of Your Pants: He enters a swimming competition despite the fact that he freezes water on contact. (Debatable, as this might have been his plan, and he may have had control over the water, thus the reason why it spread so quickly in Wipe Out.)
 * Can't Stop Coffin: He, along with Toothy and Russell, fails to notice Cuddles' absence when he goes to retrieve the baseball, and should have been aware of the long amount of time it took Cuddles to retrieve it.

Splendid
In a manner similar to Pop and Lumpy, Splendid frequently screws up his superhero duty, often making things much worse. This is due to putting his own needs first or simply out of dumb decisions.
 * Helping Helps: He flies into a branch, which causes Giggles to be decapitated.
 * Better Off Bread: He catches a falling Giggles, but fractures her back in the process. He flies so fast that her eyes detach from her sockets, and he presumably kills a seal and two seagulls in an oil spill. Then he flies into space to blow up an asteroid, still carrying Giggles and skinning her face.
 * It's a Snap: He decapitates Lumpy with his laser vision.
 * From Hero to Eternity: When he tries to save Cuddles through mouth-to-mouth resuscitation, he blows the rabbit to pieces and deafens Giggles. Later he cuts a giant snowball in two, killing Toothy and Petunia, who were inside it. He then whacks it away with a tree, not checking to see if anyone was in the tree house. He does not remove Lumpy from a truck before using it to stop the other snowball. This plan ends in the town being flooded and several characters sinking to their deaths in a whirlpool. Finally, he kills Cub by putting him in a dryer, not checking to see him inside his laundry basket.
 * Gems the Breaks: In an attempt to stop Lifty and Shifty, he sets Giggles and Petunia on fire. He also blows kryptonut dust away, resulting in it blowing back to his face, and holds back vomit.
 * See What Develops: He fails to save Handy and Mime simply because he had nowhere to change out of his disguise. Then he mistakenly attacks Giggles, thinking she was the Mole. He flies off so fast that Giggles and a nearby Toothy are shredded. Finally, he freezes Cuddles with his ice breath and breaks him in an attempt to thaw him out.
 * Wrath of Con: He sends a pencil tip through the heads of Russell, Disco Bear, and Mime. Then he accidentally deafens, suffocates and kills a crowd of fans, also destroying the convention center. Finally, he gets Sniffles crushed by a chunk of debris, which he could have tossed aside before agreeing to give him an autograph.
 * Breaking Wind: After tying Lumpy to a microphone cord, it gets caught around his leg and he squeezes Lumpy to death. Then he flies through Cuddles, does nothing to save the victims of the tornado, and dooms the entire planet because of his book pages. The wise decision would have been to leave the book at home.

Flippy/Fliqpy
Similar to Handy, both sides of Flippy are less prone to make stupid mistakes, possibly because of his age and experience in the military. However, he does have a few.
 * Party Animal: Good Flippy drinks Mime's liquefied remains, even though it is the color of blood and he used one of Mime's antlers to stir it. Also, despite the amount of carnage in the room, Flippy does not even seem to notice (or care about) the gore around him.
 * Hear Today, Gone Tomorrow: Fliqpy rings on Lumpy's doorbell and waits for the moose to answer, taking so long that he leaves. He could have just burst in through the door and killed Lumpy anyway. He does not make any attempt to move out of the way of the swinging log, which would have hit him even if it had hit Lumpy first.
 * Double Whammy Part I: Good Flippy gives Handy a foam finger, not noticing his obvious disability.
 * Remains to be Seen: Fliqpy accidentally kills himself in truck crash.
 * Operation: Tiger Bomb: Good Flippy throws a slice of pizza instead of a knife at the Tiger General. He should have been paying attention.
 * By The Seat Of Your Pants: He goes out to watch the swimming race, despite hearing the gunshot on TV and thus knowing it was going to happen.

Lammy
Despite her newness to the show, Lammy has already proven herself capable of making many stupid mistakes.
 * Every Episode She Stars, is Featured, or Appears in: Carries with her a serial killer (or who she believes is one), even though every time he does something bad she gets blamed for the crimes. (Debatable, because she may fear what he would do if left alone and feel it her duty to be there to stop him.)
 * Royal Flush: She never notices that a certain pickle just crawled into one of the sandwiches she was about to serve when she should at least have seen his inanimate form. She tries to take the nozzle out of Petunia's eye and later reverses it instead of simply turning the vacuum off.
 * You're Kraken Me Up: She does not see the tentacle controlling Giggles, and even starts cheering when Lumpy "saves" her.
 * All Work and No Play: She, along with Nutty and Sniffles, decides to play on a playground that is under demolition.

Mr. Pickels
Due to his newness on the show and very little screen time as a living creature, Mr. Pickels has almost no acts of stupidity and what he does have is debatable.


 * A Bit of a Pickle: Tries to kill a teddy bear and a sock puppet as if they were living creatures. (Debatable because of his obvious psychopathic nature and their companion-like state.)

Other
Even though the main characters are the best at having these obviously having more development. Reoccurring, Minor, Generic, and even One-Time Characters can have their own acts of stupidity as well, please no non-anthropomorphic animals though.
 * Helping Helps: Giggles' Mom accepts an acorn with a crudely drawn face as her daughter's head and doesn't notice when it falls off.
 * Tongue in Cheek: The Ants let a drawing on Sniffles' finger inside confusing it for a real ant.
 * Autopsy Turvy (Double Whammy Part II): An unseen Generic Tree Friend drives a chicken truck on the sidewalk and runs over Flippy in plain sight. (Debatable, seeing as he could have done it out of fear that Flippy might be flipped and would most likely have killed him if he was.)
 * Operation: Tiger Bomb: Tiger General as well as his soldiers don't question that someone wearing an enemy uniform is delivered a pizza to their base in the middle of a battle field.
 * A Tiger Soldier picks up what he thinks is an apple, but when he realizes it's a lit bomb he holds on to it, despite having ample time to throw it away.
 * Mirror Mirror: Splendont drops a train full of passengers UPSIDE down and tries to beat Splendid by pushing the moon to earth killing many Generic Tree Friends which was clearly not his intention.