Sheldon J.Plankton, most commonly known as Plankton, is one of the ten main characters of the SpongeBob SquarePants franchise. He is a planktonic copepod who runs the Chum Bucket restaurant alongside Karen, a waterproof computer who is his sidekick and wife. The Chum Bucket is highly unpopular in Bikini Bottom because it serves chum, a type of bait made from fish meat