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 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 his actions.
 * Water You Wading For: Cuddles jumps into a lake despite the fact swimming is not allowed, which Flaky points out. Because of this, Cuddles is attacked by creatures in the lake and crushed by a whale.
 * Sweet Ride: He doesn't look where he's skating, causing him to crash into a staircase.
 * 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's on the other side (in this case, a deep hole where he gets trapped in a coffin, burnt, drowned, and subsequently killed).
 * Change of Heart: He plays soccer with Handy's heart.
 * Dunce Upon a Time: He visibly and audibly moves in his hiding spot giving away his location to Giant Lumpy. (Debatable, because he couldn't help to sneeze)
 * Aw Shucks!: He drives past a boom gate that, although malfunctioning, was clearly trying to go down, indicating that a train was coming.
 * YouTube 101: Subscriptions: He believes that Giggles was actually on a date with Disco Bear despite her obvious hatred of the bear.

Giggles
Like most characters, Giggles is blissful ignorant and is unaware of hazards until the last minute.
 * Better Off Bread: Giggles skips through flowers until, not watching where he was going, she falls off a cliff. (Debatable because no one could of seen the cliff with all those flowers.)
 * Every Litter Bit Hurts: She puts a wooden hair brush in a plastic recycling.
 * Something Fishy: After Russell's Piranha jumps in 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?)

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 before hand, he pierces a needle all the way through Nutty's cheeks so that none of the Novocain even entered 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.
 * 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 because he it was a reaction, instead of a thought.)
 * 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 because Mime didn't 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 because this could be a prank, as he is know to be rude.)
 * 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 kills him.
 * His Smoochie: He eats a rotten Easter egg with little thought, poisoning himself seconds later.

Lumpy
Lumpy is considered by most fans as the least intelligent and dumbest character in the series and is responsible for the majority of the stupid acts committed in the show. While famous for getting others killed, his stupidity maybe to the point where he can be regarded by some as being retarded. 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. (Debatable because they did keep tell him to spin it faster.)
 * Wheelin' and Dealin': He wears a snorkel and scuba mask in a car race. (Debatable because the snorkel was more silly than stupid and the scuba mask would have served the purpose of keeping the wind out of his eyes so he can clearly see the road better.)
 * Treasure Those Idol Moments: He runs over Flaky in clear sight. (Debatable because the Cursed Idol was in the car)
 * Dunce Upon a Time: He sticks a fork in a plugged in toaster 3 times. (Debatable because he was simply after Flaky and didn't seem effected much by the electrocution, this still caused him pain)
 * You're Bakin' Me Crazy: He brings Petunia a blood-covered cake and stupidly says "Merry Christmas!" at her birthday party. (Debatable because possibly more silly than stupid.)
 * Meat Me for Lunch: He doesn't seem to care care at all that Lifty & Shifty were killed, and used their remains to make meat for his butcher's shop. (Debatable because Lumpy not caring that the raccoons were killed and feeding them to his customers simply could of showed his vengeful side; However, he looks surprised when Petunia did realizes she's eating someone).
 * It's a Snap: He falls for a bear traps baited with cheese.
 * Snow What? That's What!: He lies shirtless on a hammock with a drink... in the winter. (Debatable because he doesn't seem to be shivering or showing signs of hypothermia.)
 * Happy Trails Pt. 1: He isn't paying attention to the road (even walking away from the wheel), causing the bus to crash onto a desert island. (Debatable because Petunia and Mime took his attention away from the road.)
 * Class Act: He instructs Toothy to go on with his act despite the other play actors' injuries (Debatable because this was likely done out of apathy, not stupidity). He also casts Nutty in a play that has a character dressed as a candy cane. (Debatable because it is unknown if anyone knew about Nutty's addiction)
 * Rink Hijinks: He wears skis at a rollerskating rink while wearing exposed boxer underpants, though they might have been swim trunks. (Debatable, because this is more weird than stupid since it does get the job done and he may have trouble balancing on rollar-skates and was tired of falling on the job.)
 * 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, saws Cuddles' in half due to a magic trick, and later uses up the blood which Cuddles needed to survive.
 * 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 wrong leg which wasn't 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 isn't 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 have likely cut off his own limbs with the chainsaw and even if he didn't, 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 (Debatable, because he was doing this carelessly because he was in panic, however, not stupidly). He also doesn't notice a rhino's horn obviously went through Toothy's head, and mistakes a baboon for Sniffles (or just doesn't care).
 * 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. (Debatable: he may have not noticed Mime impaled on the board or didn't care since it still works)
 * Don't Yank My Chain: He falls for Lifty & Shifty's foolish disguises and arrests Handy and Mole. He leaves the cell open with the keys near it. He takes several seconds to realize that Handy and Mole had gotten away (Debatable, because he may have been busy). He uses part of Mole's sweater (a clue to finding them) to blow his nose.
 * Concrete Solution: Looks inside a nail gun and fires it. He was lucky it wasn't plugged in.
 * Wishy Washy: He was walking in with his shoes dirty, then exited and came back in only to realize that there is a mat underneath him, and when Petunia chokes on a glove, Lumpy puts his plunger into Petunia's mouth in order to help her. (Debatable because between the extreme issues with Putunia'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 foolishly plays with a lit match, which is ironic considering his fireman job (Debatable, because he's playing it in such a way that won't cause disasters).
 * As You Wish: He also sets Cub on fire and gets him run over by a firetruck. (Debatable, it really depended on how Pop worded his wish (whih 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. Doesn't pay attention to the group enough. Takes a nearly broken bridge over a strong one (Deabatable because this was out of fear, so he wasn't paying attention.).
 * A Change of Heart: Lumpy repeatedly losing the normal sized hearts due to him not paying attention.
 * Blast from the Past: He pushes his body so hard on a seesaw that the handle impales him. Later, he repeats his (Debatable) stupid act that he did in Spin Fun Knowin' Ya.
 * Idol Curiosity: He mistakes ice in Toothy's drink for an iceberg. (Debatable, because this was because of the Cursed Idol)
 * Home Is Where the Hurt Is: He folds the blueprints of Giggles' new house into a origami crane. (Debatable because he really just did 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 destroyed his house while trying to kill a crow, and thought Toothy's corpse was his scare-crow. (Debatable because to be fair, Lumpy might not have known it was Toothy or simply did not care as long as he could serve as a scarecrow)
 * Wingin' It: He uses many electronics, despite Mime telling him not too. Later, he takes all five parachutes, and than fails to properly wear even one of these parachutes, so in the end, it didn't save him.
 * Tongue in Cheek: He mistakes the skin from Sniffles' hand as his glove and his organs as a mini-golf course. (Debatable because he could have known it was Sniffles' hand and his organs, but he just didn't care as long as he had fun playing golf)
 * I've Got You Under My Skin: He tries to stop Sniffles from traveling further up his body, but ends up severing his leg (Debatable, because this was a weird and unexpected result to a logical attempt). He is also shown to have numerous strange items, including a plane propeller and a bear trap, inside his pockets (Debatable', because this may just be for his 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 because the pogo stick offered more versatility).
 * Hear Today, Gone Tomorrow: He doesn't realize his can was on his butt and ran 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 because 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 1 and Part 2: He hypnotizes himself, making him act like a chicken. This is later seen in part 2, where he is inside a chicken truck trying to lay eggs. Also, in Part 1, 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, because this could have been done as a way to test what causes him to flip out)
 * Can't Stop Coffin: He buries what was originally an empty coffin, fills the hole with water (Debatable because this could have been done to extinguish the fire), and leaves his truck in reverse, driving it into the grave, 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, because this may simply be bad aiming).
 * Something Fishy: He uses the fish bowl as the helmet.
 * I Nub You: He sews Handy and Petunia together, and ends up sewing his own arms on them. (Debatable because he likely was just missing body part and was really just trying to find a way to keep them both alive and that was the only option.)
 * See You Later, Elevator: He uses an elevator during a fire, which isn't safe. He tries CPR on the lower half of Cuddles' corpse, and uses to much pressure, and explodes the corpse.
 * Milk Pong: He chokes on a ball, later drinks bleach instead of milk, doesn't notice a rat in the cup (twice) (Debatable, because like with Giggles, who really looks in their drinks?), and tries to get the ball out of a wood chipper with his bare hands.
 * The Chokes on You: He eats donuts while working (Debatable because this was more lazy and selfish than stupid), and doesn't chew before swallowing.
 * Brake The Cycle: He spills too much gasoline while pouring it into his motorbike, which causes him to get burnt to death.
 * All In Vein: He leaves Giggles in the fridge for too long, causing her blood to harden (Debatable because who hasn't done this with food items?). He later drinks too much blood, causing him to go overweight, and be unable to get out of danger.
 * No Time Like the Present: He brings Handy a pair of mittens, ironic considering his lack of hands. (Debatable because this is a common gag and he might not have even been the one to wrap or choose the gift.)
 * You're Kraken Me Up: Instead of rescuing Russell, he saves the kraken 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. (Debatable, because no one else noticed this either.)
 * All Work and No Play: He attempts to save Nutty by jack-hammering the top of the wall, resulting in his torso getting completely mangled. Later saves Sniffles, but is distracted by Lammy, resulting in him getting smashed to pieces by the excavator's buckets closing in on his head. (Lumpy ironically, knows Lammy is already impaled through the brain earlier in the episode, debatable, because it likely distracted him because he thought she was dead and is now walking on her own with an injury that should be impossible to survive which is very distracting)
 * A Vicious Cycle: He eats chips out of Disco Bear's brain. While hiding in from a possessed tricycle, he bites a chip and the crunch noise blows his cover, and drinks bear on duty.
 * Dream Job: He messes with the television so much that Sniffles' dreams become erased and the TV turns off. (Debatable, because to be fair, he likely had no idea that's what he was doing and didn't have many ways to realize it's Sniffles' fault for making it possible for him to do this.)
 * Ski Patrol: He messes up and causes the deaths of numerous characters. (Debatable because this could also have been 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. (Debatable because Giggles really shouldn't have been standing there and he likely wasn't expecting her to be as if she was there, he did swing at the right spot.)
 * 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 isn't by itself a sign of stupidity.)
 * Kringle Frosty: He skis over Sniffles and Toothy, killing them. (Debatable because he might have missed them because he plowed through their snowman, causing him not to see.)
 * Strain Kringle: He throws a rock at Cuddles and Toothy, when a snowball would have been more preferable (Debatable because he was 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 the film wrapped around his body. (Deabatable because it could be said that all cases were more careless than stupid because he was in a rush.)
 * Moppin Up: He forgets (or neglects) to put a Wet Floor sign while mopping, causing Sniffles to break his head. (Debatable, because he was currently in the process of mopping so the sign shouldn't have been necessary and considering that Sniffles didn't notice Lumpy mopping, he certainly wouldn't have needed the sign)

Petunia
Petunia may occasionally make mistakes, mostly caused by her OCD.
 * Wishy Washy: After getting increasingly dirty trying to get clean, Petunia resorts to skinning herself alive using a potato peeler. (Debatable because she lost her stability from seeing Lumpy's corpse and because of her severe obsessive-compulsive disorder (OCD). Also, downs a whole bottle of mouthwash, an act that could have killed her.
 * 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.

Handy
Handy doesn't make as many mistakes as others.
 * Home Is Where the Hurt Is: Was it his idea to invite Lumpy to build Giggles' home? (Debatable because he wasn't involved in the discussion on what to do so he might have been there by chance)
 * Don't Yank My Chain: He trusts Mole to use a mallet to hit a chisel he held between his teeth. He also could have looked for someone working at the sawmill to remove his chains. Instead, he attempts to cut off the chains using a train. (Debatable because he might have looked off screen and found no one)

Sniffles
Despite being considered by most as one of the most intelligent characters in the series, Sniffles has made many illogical mistakes.
 * Spare Me: Attempts to toss a bowling ball using his snout, leading his head to be torn off.
 * Tongue Twister Trouble: Uses his tongue to catch an ant on ice, which would have stuck to the ice even if the ant hadn't 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 stopped from this course.
 * Suck It Up: He makes his invention with a ridiculously flexible nozzle to where it can get stuck to the side of his head with the other side still attached to his face. He also doesn't try to remove it from is 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.
 * From Hero to Eternity: has trouble trying to beat Nutty in a game of Checkers.
 * Party Animal: 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 drives off in the engine with Cuddles still up on the lift. He also uses a wood ladder to get to the window of a house that the fire's clearly 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.
 * 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: Let's the Mole make and lead with the map. He designs a lookout post that isn't shatterproof.
 * 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, leads him to create various time anomalies. He also shouldn't 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 fate.
 * 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's 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. With his medical experience, he should have known that he was supposed to take away his hammer and screwdriver so he doesn't get hurt from them, turn of the strobe lights, and wait it out.
 * Wingin' It: Being the only pilot operating a plane, it was 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 ways. This happens in other episodes but here he doesn't have the show's lack of continuity as an excuse. Also, makes the helmet to control the helmet so that all the Brother Ant had to do was reverse the wires to give him complete control of Sniffles' body was very stupid.
 * Easy Comb, Easy Go: He just stands there as Disco Bear sticks his head into the cotton candy machine. (Debatable)
 * I've Got You Under My Skin: Despite staring right at her (unlike Lumpy who was understandably focused on the door), he takes a long 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 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 keeps his ticket in his pocket when it's supposed to be around his neck and forgets it's 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): Either gives or lets Nutty take a chainsaw into his padded cell.
 * Peas in a Pod: He blatantly walks right into a Pod Lumpy and the Blurb points out, he would have walked into the wall if it wasn't there.
 * Something Fishy: He puts his hamster right next to Russell's piranha. He also doesn't even notice the fishbowls 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, then, when the alarm goes off they don't 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 slides right into wet cement.
 * Pet Peeve: He brings the Blob out in public and lets it hump Lumpy's leg, despite knowing the danger. 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 Sniffles gets his scalp sliced off.
 * Spare Tire: He tries to fix a long dead Giggles by replacing her missing middle with a tire. Note that though the heart rate monitor started, the air could have just pushed some her blood into artificial circulation. (Debatable)
 * Camp Pokeneyeout: Uses a rapid-shot slingshot, which causes many of the deaths in this episode.
 * Dream Job: He had designed his dream machine where 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.
 * Class Act: The entire fiasco all started when Nutty bit a chunk off Sniffles' body, dressed in a candy cane costume.
 * 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 one last bit of the bridge holding two halves together, leading him to be violently ripped in two.
 * Chew Said a Mouthful: Fractures his jaw trying to bite a jawbreaker, cuts his braces loose, 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 Nutty try to sneak out the fire exit, then, when the alarm goes off they don't even exit, but instead stand there and stare.
 * 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, to which he gets impaled on.

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 a 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.
 * 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 burnt 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 didn't know Cub was right behind the door.)
 * 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.

Cub
Cub's stupidity is excusable, since he is very young and is naive about the concept of death.
 * Rink Hijinks: He rips Lumpy's heart out using a claw in a toy machine, then hugs the organ thinking it is a toy.
 * Cubtron Z: After being reincarnated into a giant robot, he uses Cuddles, Giggles and Petunia as crayons to draw on a building.

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.
 * 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.
 * Easy Comb, Easy Go: He sticks his head inside a cotton candy machine. He leaves the back of the 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 doesn't seem to be that high. In fact, it could be comparable to Lumpy's at times. However its possible that the reason Russell does stupid acts is because of his blurry eyesight as seen in A Sight for Sore Eyes
 * Whose Line Is It Anyway?: He swallows a live pufferfish and it inflates in his throat.
 * In a Jam: 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.
 * Something Fishy: Doesn't seem to notice his pet piranha is missing or realize Lumpy put the fish's bowl over his head.
 * Bottled Up Inside: After a glass bottle impales his chest, Russell pushes it further into his body just to fit into his car. He doesn't 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: Rips out Disco Bear's spine and head, thinks he's 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.

The Mole
Some may consider the Mole's actions acceptable since he is blind. But there are times this rule won't apply.
 * Spare Me: He doesn't wonder what's blocking the holes in his "bowling ball", instead roughly jamming his fingers right through Sniffles' glasses.
 * Blind Date: He can't tell the difference between a dead Lumpy and Giggles besides many non-visual indicators such as heat, size, and voice before death.
 * In a Jam: Despite Cuddles informing him about a mistake (giving a button instead of money), he makes Cuddles donate again. He doesn't find it weird that a chair was suddenly where his patient laid, and proceeded to sit on Cuddles' corpse.
 * Wipe Out: 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.

Mime
Mime has caused quite a few of these, with 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: Somehow doesn't notice Lifty and Shifty are watching him, despite the fact that they aren't even hiding.
 * Who's to Flame?: Assuming he could talk, why did he mimic talking on the telephone, instead of actually talking? And even if he can't, why use the phone in the first place?
 * Dunce Upon a Time: Stays in the broken jar even when about to be stepped on.
 * Mime To Five: 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, and letting Sniffles drown.
 * Something Fishy: He also doesn't even notice the fishbowls on Russell's head instead of the helmet.

Flaky
In contrast to the blissfully 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.
 * Happy Trails Pt. 2: Jumping the Shark: She completely forgets that she's a porcupine and leans back against the inflatable life raft popping it.
 * Let It Slide: Considering her fear of water, why did she even go to a water park in the first place.
 * Take a Hike: She accidentally kills an eagle chick trying to return it to its nest, and gets killed by its mother as a result. Usually it is common sense to leave a baby bird alone considering how protective their parents are.
 * Dunce Upon a Time:She visibly and audibly moves in her hiding spot giving away her location to Giant Lumpy.
 * 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.
 * Without A Hitch: Let's her hallucinations distract her from driving, causing her to crash into a pole.
 * The Chokes On You: Somehow doesn't notice that the "doughnut" she had got was Lumpy's flesh. Like Lumpy did earlier in this episode, she swallows a doughnut without chewing it first. She ends up choking and possibly dies.

Lifty
Despite being considered by most as pretty much the same character, Lifty seems to have more of the brains for the raccoon duo but he still make mistakes, usually along with Shifty though.
 * Wheelin' and Dealin': Doesn't notice until the race is about to start that their cart didn't have wheels or that it didn't have a steering wheel until one was needed despite having presumably made the cart with Shifty.
 * Meat Me for Lunch: He and Shifty keep a shoe in their fridge.
 * 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 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: 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 expecting it to get far with it. Also they stay in the car when it's 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 an a very low intelligence level, and causes way 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 didn't know that cars need wheels.
 * Meat Me for Lunch: They 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.
 * 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 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, expecting it to get far. Also they stay in the car when it's 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 the van presumably to save him when it would have been better for Lifty to jump into Mole's van. He also doesn't 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. The only case of his stupidity would be the one instance before he became frozen.
 * 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.

Splendid
Under a similar light 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 and 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 become detach from her sockets, and he presumably kills a seal and two gulls in an oil spill. Then he flies into space to blow up an asteroid, still carrying Giggles and skinning her face. The asteroid breaks into hundreds of pieces, one of which kills Toothy.
 * It's a Snap: He unknowingly sends a bear trap into Cub's head and decapitates Lumpy with his laser vision.
 * From Hero to Eternity: Trying to save Cuddles through mouth-to-mouth resuscitation, he blows the rabbit to pieces and deafens Giggles. Soon 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 doesn't 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. And he kills Cub by putting him in a dryer, not checking to see him inside his laundry basket.
 * 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 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 with 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

 * 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 anyways. Doesn't 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: Gives Handy a foam finger not noticing his obvious disability.

Lammy

 * 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.
 * Royal Flush: Never notices that a certain pickle just crawled into one of the sandwiches she was about to serve when she should have at least seen his inanimate form.
 * All Work and No Play: She, along with Nutty and Sniffles, decide to play on a playground that is under demolition.