Continuity Errors

A continuity error is defined as any time in a piece of fiction where an event in the plot (whether small or large) contradicts information previously received. It has been stated that Happy Tree Friends relies largely on an absence on plot continuity to function. This allows them to kill any of the characters and still have them available to use in later episodes. However, in addition to characters coming back from the dead and/or miraculously losing major injuries, there are many other cases of continuity errors from episode to episode and even some within the same.

Cuddles

 * In the HTF Break Seize the Day, Cuddles is clearly shown to suffer from photosensitive epilepsy. However, in In a Jam, he is completely unaffected by the flashing lights, even though they give Handy a seizure. (It is possible that Cuddles did not suffer a seizure because he was not focused on the lights, or due to the fact that he only had one eye, as obscuring one eye can lower the risk of seizures.) Though, he was also seen admist strobe lights in Keepin' it Reel and didn't have a seizure (Though these might have not been the correct frequency for seizures).

Giggles

 * Giggles has dated several different male characters throughout the series.

Toothy

 * Toothy is presumably allergic to bees, as he gets stung by one in the eye in The Carpal Tunnel of Love, which results in it getting swollen. However, in Aw, Shucks! he encounters with a swarm of bees, which start to sting him numerous times; but Toothy's body doesn't even swell up a little, which contradicts his "allergy". There are two possible explanations to this last fact: The theory about Toothy's allergy is just a rumor from the show's audience, or the bugs that stung him in Aw, Shucks! are just wasps instead of bees.

Lumpy

 * The size of Lumpy's brain changes many times throughout the entire series.
 * In Snow What? That's What!, Lumpy is shown relaxing shirtless in a hammock without being affected in any way, but in Just Desert, he is dressed in very heavy winter clothing to go hiking in the mountains. Furthermore, in Snow Place to Go, he is shivering in the cold along with everyone else (though it is possible that he can only take the cold for a certain amount of time).
 * In All Flocked Up, Lumpy is unable to climb a tree, so he has to come up with other ways, but in Doggone It, he climbs one effortlessly to escape Whistle. (This could be due to the fact the tree in All Flocked Up was much larger in circumference).
 * In Concrete Solution, Lumpy has blue eyes, but in Wishy Washy, his eyes are green.
 * Lumpy has hoofed feet in Every Litter Bit Hurts, but toed feet in Wipe Out!.
 * In Wingin' It, Lumpy fell out of an airplane and upon landing, had his leg bones push out his shoulders but survived for the time being but in All Flocked Up, he fell out of a tree and splattered upon landing.

Handy

 * Handy's arms are cut off at the elbow in The Wrong Side of the Tracks, but they are cut off at the wrist in House Warming, Concrete Solution, From Hero to Eternity, and Double Whammy Part I.
 * Handy's hardhat can also come to debate. It is shown to be able to withstand objects such as glass (Ipso Fatso) and even car tires (Pet Peeve), yet offers no protection against objects like a lawnmower (A Sight for Sore Eyes) or helicopter blades (Who's to Flame?).

Nutty

 * The size of Nutty's brain changes between episodes.
 * In Concrete Solution, Nutty has a bowl of fruit on top of his fridge but in Chew Said a Mouthful he is shown to hate fruit (Debatable as it could be for decoration).

Sniffles

 * A glaring example would be how the length of his snout changes throughout the series, starting out very long and later becoming a lot shorter.
 * However, this was done as a design change to make him cuter.
 * The length of Sniffles' tongue also varies. In Crazy Ant-ics and Tongue in Cheek, it is shown to be very long, but in Tongue Twister Trouble, he runs out of tongue while sliding much sooner.

Flaky

 * In From A to Zoo, Flaky is clearly shown to be afraid of chicks, but in Take a Hike, she saves an eaglet without any sign of fear. It is possible, however, that she is only afraid of certain kinds of birds.
 * Similarly, in both Ski Ya, Wouldn't Wanna Be Ya! and Mime to Five, Flaky is very clearly shown to suffer from acrophobia (fear of heights). However, once again in Take a Hike, she was not afraid to climb the tree to return the eaglet to its nest, and in Ski Patrol, she seems comfortable and happy on a ski-lift. (However, in Mime to Five, it could have been performance anxiety.)
 * Handy is shown teaching Flaky how to drive in Easy Comb, Easy Go, even though she is seen driving alone in Concrete Solution, which premiered earlier.
 * In Ski Ya, Wouldn't Wanna Be Ya!, Flaky is afraid of skiing even extremely small "hills", but in Ski Patrol, she seems perfectly happy going skiing.

The Mole

 * In Stealing the Spotlight, it is implied that The Mole cannot feel pain, as he does not notice that his thumb is on fire. However, in Double Whammy Part II he, notices when he cuts his foot on a piece of glass. (However it's possible that he can only feel pain in certain parts of his body).
 * His hearing in episodes can vary from good, to average, to almost completely deaf.

Russell

 * In Sea What I Found, he needs to wear scuba gear, but in Off the Hook and Sea of Love, he is shown without it. (It is possible that it is simply a matter of depth and/or time difference.)
 * Sea What I Found shows him to be able to take off his peglegs much like shoes, but in You're Kraken Me Up and Idol Curiosity, they do not come off when pulled on.

Cro-Marmot

 * In From Hero to Eternity, Cro-Marmot was seen floating in the flood without having any effect on the water (though it's probably because the water was moving fast). However, in Wipe Out! and Swelter Skelter, he was shown to have very powerful freezing abilities. Later on, in By The Seat Of Your Pants, he also entered a swimming competition but to be fair, we never see him in the water.

Flippy/Fliqpy

 * When flipped out, his eyes vary from yellow, green, blue in Remains to be Seen, any variation of the first two, and even staying normal pac-man black in his debut. (Though the blue eye variation is most likely a goof).
 * In Double Whammy Part I, it is revealed that if you dump water on Fliqpy, he will flip back to Good Flippy. However, in By The Seat Of Your Pants, Fliqpy went into the pool to chase after Lumpy without flipping back. (This could be due to the fact that in Double Whammy Part I, him being splashed with water was a surprise to him, while in By The Seat Of Your Pants, he was fully expecting the water).

Splendid

 * Splendid's vulnerability often comes into question. Despite being able to survive so much as the moon hitting the planet in Mirror Mirror, he was confirmed to have died in an explosion in Class Act.

Mr. Pickels

 * In both animate and inanimate form, the size of Mr. Pickels repeatedly changes, sometimes even in the same episode.

Non-Character

 * The time period of the show constantly varies to complete impossibility.
 * Many episodes show a beach in or extremely close to town. However, Who's to Flame? shows an overview of the town depicting it as completely land-locked.