Sheldon J. Plankton is one of the two main villains in the series. His computer sidekick Karen gives him his evil plans. He terrorizes some citizens, and tries to steal the Krabby Patty formula. He doesn't have any pets, nor wears anything as he is small. However, in Plankton's Pet, Plankton picks up a pet a the shelter named Spot. It is shown that the Chum Bucket is almost always empty. He is shown to be afraid of Pearl according to One Coarse Meal. It's shown that he is the same age as Eugene Krabs.