Sheldon J. Plankton, more 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.
Both Plankton and Karen are the two main antagonists of the franchise. There are also several episodes in which Plankton acts as a sympathetic anti-hero. Plankton despises his rival, Mr. Krabs, for running a successful restaurant because his own business rarely gets any customers. His main goal is to steal Krabs' secret formula for Krabby Patties and running Mr. Krabs out of business. Karen gives him a variety of plans to steal it, but their efforts always end up failing in the process.
