Flippy is a light green bear with dog tags, a green beret with checkered crest, and a camo shirt. He fought in the W.A.R (Weaponized Animal Regiment). According to writer Warren Graff, Flippy is mostly based on John Rambo. He rarely appears in the series, most likely due to his repetitive behavior in most of the episodes in which he appears. He lives in an overturned log resembling a quonset hut, a structure used by the U.S. Armed Forces or a big, fancy house. Flippy is trained in hand-to-hand combat, and has never been seen using guns to kill other characters (although the closest thing he did to using a firearm was using a stapler as one and a bow with a torch).
Flippy has a severe case of post traumatic stress disorder. Whenever he sees or hears something that he associates with killing or that reminds him of war (e.g., loud sounds, gun noises, et cetera), he goes insane, becomes extremely aggressive and kills everyone around him, due to him thinking he is back in the war. While insane, his eyes turn a different color, his voice changes, his teeth turn sharp, and he becomes very aggressive. He first developed this aggressive change after facing a life or death situation while hiding in the dead body of one of his comrades as shown in one of his "War Journals".
Although Flippy can be the most cruel and violent character in Happy Tree Friends, he is considered to be one of the most sociable and kindest of characters when hes not Flipped-out. This is proven in several episodes where he is seen doing social activities with some of the other characters such as going to the movies and playing hide and seek. In most of the episodes where he appears, he is shown as friendly and social before he has a flashback, or as many people say "flipping-out." After he "flips-out", he does not remember the rampage that follows afterward and occasionally he realizes what he has done and is visibly disturbed. In "Double Whammy", he finally realizes his problem and goes to Lumpy the psychiatrist for answers. Lumpy tries using hypnosis on Flippy, but he accidentally hypnotizes himself into thinking he is a chicken. Flippy then goes home and after a bad dream he sees an evil version of himself trying to kill him. after a long battle with his evil side across town, evil Flippy takes the good Flippy to a warehouse. The evil Flippy then tortures the good Flippy but, he escapes and then they briefly fight. Then evil Flippy takes a knife and is able to hold good Flippy From behind the neck while good Flippy resists, and then they move towards a mirror. That's when Flippy sees that he is only fighting himself and the Evil Version of himself was only in his imagination. Finally, an army of evil and Good Flippys fight a bloody battle leaving good Flippy as the only survivor. Flippy sees that he imagined the entire battle and he has not removed his evil presence.
So far, Flippy has killed every character, with the possible exceptions of Splendid, Lammy, Mr. Pickels, and Cro-Marmot. He is often considered to be the most popular character of Happy Tree Friends.
Flippy is voiced by Aubrey Ankrum. Kenn Navarro voices Good Flippy after season two, though through sampling Ankrum remains the voice of Evil Flippy.