Flippy started his life in a simple town. He was called up to go to the war in which he experienced so much blood, gore, and torture that he became traumatized and developed the PTSD disorder, in which whenever he sees or hears anything that reminds him of the war, he turns evil and goes on a killing spree.
Recently, Flippy has been able to control himself better than before after realizing his dark side and fighting it off in a canonical episode. He has a unique way of attracting many female characters which in turn has gained him a lot of smitten girlfriends.
In fact, some of his girlfriends are used to be army girls, but soon changed due to a picky fandom.
He is considered the best main character of Happy Tree Friends, seeing as how he has so many fans.