Plankton is a fictional character in the TV cartoon Spongebob Squarepants. Plankton is a technologically savvy, deep-voiced plankton with one central eye. He is the smallest of the main characters. Plankton is a copepod.

Plankton is Mr. Krabs's business rival. He runs a competing restaraunt where no one eats called "The Chum Bucket" which is located directly across the street from "The Krusty Krab". Plankton seems to have a vague plan to take over the world which involves getting hold of the secret recipe for the Krabby Patty served at "The Krusty Krab". Plankton is about the same age as Mr. Krabs. Plankton lives in "The Chum Bucket" with his computer wife.