Throughout Happy Tree Friends, the way the Happy Tree Friends are introduced, as well as how the title sequences and closing credits are displayed, have evolved over the years, each all the more different from each other.
Internet Season 1's introductions involve every character coming out of a bush, going through an animation such as a gesture (a wave), then going back into the bush and disappearing. Normally, before they appear, text appears saying "This Week Featuring...", and when all of the characters have finished, another piece of text appears saying "Almost there...", followed by the episode. All this happens while the Happy Tree Friends theme song plays in the background.
The gestures the characters make while they are visible are as follow:
Splendid: Pops up with his hands on his hips (as a heroic pose) and then pops back down.
Season 2-early Season 3
In Internet Season 2, all the characters are featured in a book. The book shows more characters as it flips pages. All the characters are featured one by one on the pages. The background is usually the same color as the character.
The gestures the characters make while they are visible are as follow:
Cuddles in a yellow background, holding both his hands out.
Giggles in a pink background, posing with her hands on her waist.
Toothy in a purple background, holding both his hands out and smiling. (Goof: He has normal buck teeth.)
Lumpy in a blue background, both he and the background are upside down.
Petunia in a dark blue background, waving with one hand.
Handy is smiling while in an orange background with a few logs.
Nutty in a green background with some blue rocks, jittering.
Sniffles in a light blue background, holding a few books.
Pop raising Cub up into the air with an orange background.
Cub standing happily in an orange background (in the episodes in which Cub appears without Pop).
Flaky looking shy with one finger close to her mouth while standing in a red background.
The Mole standing in a purple background with his cane.
Disco Bear in a tan background by a disco ball while in a dancing position.
Russell in a pastel green background, standing by a river.
Lifty & Shifty in a dark green background with their trademark grins.
Mime holding a balloon animal in a purple background.
Cro-Marmot standing still with a snowy background. (This can only be seen on the website, as the first season intro is replaced with the second season intro.)
Splendid with his hands on his hips, looking important while standing with his fortress in the background.
Rink Hijinks Pop-ups
The episode Rink Hijinks features alternative character pop-ups. The most likely cause of this is that this episode was under development before the second season, and these were the original designs for the pop-ups.
These pop-ups all have the same background, the same color, the characters are outside instead of inside the background, and their poses are different (Ex. Flaky is happy instead of worried).
Flaky is standing happily with both arms outstretched.
Disco Bear looks at the viewers while dancing.
Cub stands happily with both arms outstretched. Notice the arms being raised at a higher angle.
Lumpy stands upright, both arms at his side, while looking stupidly.
Late Season 3- Season 5
These starring intros begin with the episode Wrath of Con. Starting in Something Fishy, there is also a featuring character card, which reads "Featuring a few friends:" and has the characters on a playground. Starting in Brake the Cycle, the card instead says "Also featuring:".
Each character's starring pop-up features a rhyme or an alliteration that fits in with their personality traits, in addition to almost every word beginning with the first letter of their name, this being an exception for Lifty, Shifty, Lammy (somewhat), and Mr. Pickels whose sentences only rhyme.
Cuddles is standing and smiling with his arms outstretched. C is for Cuddles - Caring and sharing is cause for charming cheers!
Toothy is holding a toothbrush. T is for Toothy - Using a toothbrush is tantamount for twinkling teeth.
Lumpy is holding a sandwich. L is for Lumpy - For a lazy lunch, try left-over loaf!
Petunia is planting flowers with a watering can next to her. P is for Petunia - Plant plenty of pretty, perfumed, purple and pink flowers!
Handy stands smiling, surrounded by tools. H is for Handy - A happy home has all the right hardware for any happenstance!
Nutty jitters with candy scattered on the ground. N is for Nutty - Nutting wrong with going nuts for nectarously nice candy!
Sniffles is doing a chemical science experiment. S is for Sniffles - Science is seriously satisfying!
Pop smokes on his pipe while Cub stands in the background. P is for Pop, C is for Cub - Paternal parents are patient and proud. Cute kids are cuddly and carefree!
The Mole stands on a platform with purple grass, with a purple-ish sky in the background. M is for Mole - Myopic, meandering marches most often lead to macabre mishaps.
Disco Bear winks with a disco ball hanging next to him. D is for Disco Bear - Don't be a drag. Get down and dance! Can you dig it? (Only main character so far in which the background is not the same color as the fur; instead it is purple.)
Russell is rowing a small boat. R is for Russell - Row, row your boat down a running river!
Lifty & Shifty have stolen bags of money. L is for Lifty, S is for Shifty - No time to be thrifty, just take what's nifty and be out in fifty!
Flippy sits on a stump and roasts marshmallows over a campfire. F is for Flippy - Fire fried food is a feast for a famished soldier.
Splendid is flying through the air. S is for Splendid - Super squirrel swooping in for the save!
Lammy & Mr. Pickels are walking and holding hands. L is for Lammy, Mr is for Mr. Pickels - Long lasting friends don't tend to be fickle. More likely, they would laugh and love to tickle!
In the Season 3/4/5 Featuring pop-ups, the text will either say "Featuring a few friends:" or, in later episodes, "Also featuring:". As of now, there have never been more then five characters on this pop-up.
Cuddles is on the slide, both his arms outstretched, while looking down.
Giggles is on the slide, both her arms outstretched, while looking in the viewer's direction.
Toothy stretches out both his arms with his eyes facing the audience. He is not featured on the slide. However in Going Out With a Bang he is looking at the slide.
Lumpy just stands stupidly when he is not on the slide. His arms are down when he faces his right. His left hand is near his mouth when he faces his left. When he is on the slide, he lays upside down, with his body taking up almost the entire length of the slide.
Petunia stretches her arms out when on the slide.
Handy stands happily while looking happily at the viewer.
Nutty is too jittery to go on the slide. However, in Camp Pokeneyeout, he is at the top of the slide, looking and waving at the viewers.
Sniffles looks in the direction of the viewer, with both his arms outstretched. In Random Acts of Silence, he does the same thing but while on the slide. However, in Camp Pokeneyeout, he stands with his arms down while facing his right.
Pop stands by the bottom of the slide. However, in Going Out With a Bang, he is seen at the top of the slide, behind Cub.
Cub plays happily on the slide with both arms outstretched.
Flaky looks in the direction of the viewer nervously, with her right index finger near her mouth.
The Mole is feeling around with his cane while facing his right.
Russell smiles at the viewer with his hook in the air.
Mime looks at the viewer while miming. However, in Random Acts of Silence, he just faces happily to his right.
Cro-Marmot stands still.
Lammy slides down while Mr. Pickels stands on the top of the slide. However, in Spare Tire, she holds an inanimate pickle in her arms.
Example of a featuring pop-up.
Lumpy's featuring pop-up.
Pop and Cub's featuring pop-up.
Lumpy when standing.
Nutty and Cro-Marmot's featuring pop-up.
Russell's featuring pop-up.
Lammy's featuring pop-up. (Mr. Pickels has yet to be counted as a featuring character)
Lammy with a regular pickle in the episode Spare Tire.