This tiny dark green plankton is called Sheldon J. Plankton and he is one of the main characters of the animated series SpongeBob SquarePants who wants to steal the secret formula for Krabby Patties and running Mr. Krabs out of business. Plankton also runs the unsuccessful Chum Bucket restaurant with his wife, Karen. The cool cartoon cursor for a mouse from SpongeBob SquarePants with Plankton and Secret Formula!
