The Why-Wolves are characters that appear in the episode "Donny." They are monsters that resemble werewolves, but have a more inquisitive nature, and will sometimes pause to give lectures. One Why-wolf explains that their species is possessed by the spirit of inquiry and bloodlust. In the episode "Donny," a Why-wolf describes his species' place in the food chain: The Why-wolves are usually kept in check by Obnoxygen, a gas produced by Donny the ogre that is deadly to Why-wolves. However, if left unchecked, the Why-wolves would eat the House People and grow in population until they attract the Cosmic Owl, who will subsequently devour them.
They resemble classic, modern werewolves, although simply by tearing away tufts of fur, they transform into more civilized versions of themselves. After this transformation, they wear grey suits and glasses. It has been seen that some Why-wolves have two heads with one eye on each.