The term "fourth wall" originated from plays in theaters, when actors would look at the audience, talk to them, or do anything else that involved the audience. Because the stage would generally have a wall at the back and both sides, this concept involves the actors becoming involved with the audience who are at the front, which can be considered an invisible wall, making it the fourth one.
Sometimes in Happy Tree Friends, something will happen that implies the characters are aware of being fictional characters in a cartoon. The Fourth Wall is most often broken in Smoochies, but has also been broken in the internet series and the TV episodes.
In Internet Episodes
- Water You Wading For: Flaky is the first to break the fourth wall by looking at the camera after witnessing Cuddles' death and nervously laughing.
- Stayin' Alive: At the end, Disco Bear is dancing for the audience and gives a growl to the audience.
- This Is Your Knife: Cuddles, Giggles and Flaky hum the show's theme song at the beginning of the episode.
- Happy Trails Pt. 1: The bus passengers hum the show's theme song at the beginning of the episode.
- A Hard Act to Swallow: An ant re-opens the closing iris and cheers at the viewer.
- From A to Zoo: The characters hum the show's theme song as they enter the zoo. Lumpy also shrugs his shoulders while looking at the audience after Sniffles hands him the camera to take a picture with him next to the baboon. He later shrugs again at the audience after the baboon puts Sniffles' glasses on. Lumpy looks at the audience again after he checks his clipboard.
- A Sucker for Love Part 1: At the beginning of the episode, Pop smiles at the camera.
- Wrath of Con: Numerous characters are squished against the screen (which is cracked; à la Petunia's Smoochie) and blood splatters slide down the screen.
- See You Later, Elevator: Mime and Sniffles look at the audience in shock/horror, after realizing that the elevator stops, possibly due to the fire alarm ringing (Debatable).
- Just Desert Blurb: A Blurb reading "Blurb placed for your protection!" is placed over Lumpy's crotch.
- I Nub You: Petunia growls at the viewer after she realizes she can't pick up a bowling ball. Similar to how Handy realizes he can't do several tasks without hands.
In TV Episodes
- The Wrong Side of the Tracks: When Sniffles' metal detector finds something for the first time, Sniffles looks at the viewer. Lumpy looks at the viewer and shrugs after finding Nutty's cotton candy near the rollercoaster.
- And the Kitchen Sink: When Pop's car lands in the water, it makes a big splash, it can be seen that there is water on the screen sliding and dripping down.
- Party Animal: Sniffles stares at the viewer when he has an apple in his mouth, Cuddles' blood starts spreading on the screen, Flaky looking at them when removing the peanut, and at the end, the iris closes on Flippy's mouth, cutting off his lips.
- As You Wish: After Mime makes his balloon animal, he looks at the viewer.
- Take a Hike: They hum the HTF theme song at the start of the episode. Later, Lumpy smiles at the viewers after he successfully extinguishes the fire on Sniffles.
- Every Litter Bit Hurts: At the end of the episode, when Giggles' heart drops out of The Mole's bag, blood from the heart squirts outside the closing iris.
- A Hole Lotta Love: After the drill machine breaks, Sniffles' and Pop's faces smash in front of what appears to be the TV screen. Also, Mime can be seen smiling to the viewers after nearly getting killed by Petunia.
- Mime to Five: Flaky breaks the fourth wall by looking at the viewers before her demise.
- Blast from the Past: Cuddles yells, "Oh my God, I'm gonna die! Not this old death again!" This implies that he knew he died in Spin Fun Knowin' Ya.
- See What Develops: Splendid looks at the audience dumbfounded after the Mole leaves with a photo of the superhero.
- Aw, Shucks!: Flaky breaks the fourth wall by looking at the viewers and laughing nervously before her death. (or she could have been looking at the target when the popcorn misses it). Cuddles also shrugs his shoulders while looking at the audience after waiting at the train tracks and not noticing the train coming.
- Wipe Out!: When a wave splashes on Flaky and Cuddles, it can be seen that there is water on the screen sliding and dripping down. Also, Lumpy grins at the viewer after his "hair" flies off.
- Wingin' It: Flaky stares at the viewer, when she pops the raft near the end.
- Easy Comb, Easy Go: In the beginning of the episode, Disco Bear waves at the camera and says, "Hey!".
- Junk in the Trunk: Lumpy's Elephant may have looked at the viewer with tears on his eyes while he was being enclosed in his cage by an annoyed and angry Lumpy
- Double Whammy: After Flippy realized he killed Nutty, he looks at the viewer in complete shock.
- Autopsy Turvy (Double Whammy Part II): After two Fliqpys tear open another Fliqpy, large amounts of blood splatter and cover the screen and slides down.
- Pet Smoochie: Cuddles waves and says hello to the viewer(s).
- Easter Smoochie: Toothy waves and says hello to the viewer(s).
- Valentine Smoochie: Giggles blows a kiss at the viewer(s).
- Summer Smoochie: One of Petunia's deaths involves her being crushed by a hose pipe against the screen, and the screen cracks before she explodes.
- Baseball Smoochie: Flaky waves and chuckles nervously to the viewer(s).
- BBQ Smoochie: Pop waves his hat and says "Hello there!".
- Olympic Smoochie: Mime throws a heavy metal ball which bounces off the side of the screen and smashes into his face.
- Halloween Smoochie: Disco Bear dances for the viewer(s).
- Party Smoochie: Nutty's car bumps into the sides of the screen.
- Science Smoochie: Sniffles' guts fill up the screen and eventually dies in the oversized guts, similar to Petunia's death from her Smoochie.
- Milk Pong: After Handy and The Mole crush Lumpy after the tree they were cutting down smashes him, Handy looks at the player (this is a game) in surprise (Debatable, he could have been looking at Lumpy's smashed body).
- Many episodes in which Handy appears: Handy growls and does his signature scowl at the viewer after realizing that whatever task he's trying to do requires hands.
- Pop-Ups: Excluding the TV series pop-ups, the characters look at the viewers.