The show's 26 characters have their own names and personalities. Unifying traits between the anthropomorphic mammal characters include buckteeth and a heart-shaped nose. Main characters include Cro-Marmot, Cuddles, Disco Bear, Flaky, Flippy, Giggles, Handy, Lammy and Mr. Pickels, Lifty and Shifty, Lumpy, Mime, The Mole, Nutty, Petunia, Pop and Cub, Russell, Sniffles, Splendid and Toothy.
Every episode begins with characters participating in an everyday activity. Throughout the course of the episode -- and through a series of unfortunate accidents -- these activities result in violence and death. While most characters die, they reappear in later episodes.
Kenn Navarro and Rhode Montijo created HTF. Montijo first came up with the drawing of a rabbit, which resembled Cuddles. Under the drawing he wrote "resistance is futile." This drawing inspired the two to approach Mondo Media, their employer, with a pitch for the show. Today, Montijo is working on his comic book, Pablo's Inferno. Navarro currently works as an animator.
Due to the show's violent nature and possible appeal to children, parents, media outlets and the Russian Media Culture Protection Department (RMCPD) have spoken out against the show. In 2008 the RMPCD banned HTF, stating that the show's episodes, "promote violence and brutality, harm the psychic health and moral development of children, attack social morality; all of this being a violation of license agreement." After catching her six-year-old son watching HTF, Washington Post writer Katherine Ellison blasted the show, suggesting it was harmful to children's psychic development.
In 2008, Stainless Games developed Happy Tree Friends: False Alarm, a physics-based action-puzzle game. The game features HTF characters, Flippy, Lumpy and Handy. The object of the game is to save the HTF characters from death using various resources found in the game. A 2008 spin-off cartoon, KA-POW!, features Buddhist Monkey, Flippy and Splendid. The characters are portrayed as superheroes trying to fight evil.