What is the name of evil character on sponge bob square pants?

The main evil character on SpongeBob SquarePants is Plankton.

He is the owner of the Chum Bucket, a rival restaurant to the Krusty Krab, and constantly schemes to steal the Krabby Patty secret formula. While he often fails in his plans, he is persistent and quite clever, making him a recurring antagonist.