Sheldon J. Plankton

Sheldon James Plankton (born November 30, 1942 ) is Mr. Krabs' nemesis and the second antagonist of the series. He operates a struggling restaurant called the Chum Bucket, located directly across the street from the Krusty Krab. His primary goal in the series is to steal the Krabby Patty recipe and put Mr. Krabs out of business. Plankton succeeds at stealing the recipe in the movie, but his goal of world domination is thwarted by SpongeBob. In the episode "Smug Alert!", it is revealed that Mr. Krabs and Plankton were once best friends, but a dispute over the Krabby Patty recipe ended their friendship.