Cujo was once the beloved St. Bernard of the Camber family who only wanted to be a good dog, but was bitten by a rabid bat in the nose when his head got stuck in a batcave while chasing a rabbit (which was shown at the beginning of the movie). Cujo then went mad with rabies and killed any person he came across including one of his own owners, conducting a murderous reign of terror until he got shot by a sheriff in self-defense. He was then resurrected by Crow Reaper, and actually belongs to the Legion of Terror which is a horror supergroup of supervillains with the three leaders being Jason Voorhees, Michael Myers and Freddy Krueger. His breed of dog is St. Bernard.