Futurama
Nibbler - a little black alien with pointy canine teeth. The crew saves him from a collapsing planet and he becomes Leela's pet. He can eat animals that are ten times bigger than himself with one bite. He poops dark matter that is used as the fuel for Old Bessie. Nibbler wears a diaper and a red cape. He is actually very intelligent and can speak, but does not show it. He staged the accident that brought Fry to the future so Fry could save the world from an attack of giant hovering brains.