Sheldon J. Plankton

Sheldon J. Plankton or Plankton is a character and the main antagonist from the show SpongeBob SquarePants. He is actually plankton. He has a big aggression towards Mr. Krabs. This is because his restaurant, the Chum Bucket, gets no service unlike Mr. Krabs' restaurant, The Krusty Krab, who sells Krabby Patties. Ever since this Plankton has been trying to steal it. Every try has failed.

History
Plankton and Mr. Krabs were great friends when they were young. They created the Krabby Patty together after the most popular burger joint got shut-down. After everyone had a patty it made their stomachs ache and cramp. After they made enough money they got in a fight and each got half of the recipe. Mr. Krabs got the half that had everything on it but the ingredient that made everyones stomachs ache. That ingredient was chum. So ever since then Plankton has been trying to steal the recipe.