Dr. Gerbil

&nbsp Dr. Gerbil was a minor villain in Courage the Cowardly Dog.He appears in the episode Human Habitrail.In the episode, he poses as a vaccuum cleaning doctor, and uses a vaccuum to suck up Muriel and Eustace.He then tells Courage that he'd been freed.He then puts them through all kinds of tests as an act of vengeance on humans for their mistreatment of animals.He later chases Courage in a waterboat, and falls off a waterfall.He survives though.