Gromit, similar to purebred tribbles, is a small, round furball. He has no eyes, arms, legs, or other appendages of any sort, only a small mouth on his underside. (Star Trek: Banshee Squadron) Unlike purebred tribbles, however, Gromit's mouth is full of incredibly hard, razor-sharp teeth, a trait bestowed upon him by his glommer genes. He can gnaw through almost any substance in time.