The Weremole is a vicious predator in the middle of Nowhere. They are based off of werewolves.
Wild and savage, a weremole seeks only to feed on rabbits or humans in a gruesome tearing-and-shaking fashion. Once bitten by a weremole, the victim will mutate into one as well. They take on the hairy and violent characteristics of their attacker, as well as the inhumane nature. The only known cure is if they are fed a strand of hair from their infecting mole. However, this only works on humans and rabbits.
When Courage was bitten by the weremole, he did not become one himself because he is a dog. The weremole's effects have been proven ineffective, therefore, Courage is impervious to this (although he still didn't like getting thrashed about).
The weremole makes another appearance in Ball of Revenge where it helps the other villains attack Courage. However Courage screams loudly which causes a big chasm to open up causing the weremole to fall to his death along with the other villains. See The Demon in the Mattress.