Sheldon J. Plankton is Mr. Krabs arch nemesis and is the antagonist in the show. Well sometimes he can be friendly, only sometimes. Ever since the Krusty Krabs got in business he has wanted the secret formula. Many many times has he failed getting the secret formula, no matter how hard he tries, he still fails. Plankton tried to open his own restaurant named the Chum Bucket which nobody eats at. Plankton has a computer wife named Karen. Plankton has a lot of criminal records in Bikini Bottom. *Pictures down below*