

The design of his body was based on the shape of a hamburger, and his face, particularly his mouth, was based on the shape of a hot dog. This friend reportedly had limited social interaction and a voracious appetite. He is based on a friend of creator Joe Murray.

According to Murray, the wallaby "was oblivious to the chaos around him." Heffer's name is derived from the word "heifer," meaning a female cow that hasn't borne a calf. His personality is based on a wallaby that Joe Murray witnessed at a Bay Area zoo. Inspiration for the show's characters: Rocko's name is taken from the animal that he's based on: the rock-wallaby native to Australia.
