Sheldon J. Plankton (The Life of SpongeBob SquarePants)

Sheldon James Plankton (born November 30, 1942) is the main antagonist in ''The Life of SpongeBob SquarePants. ''He is a tiny green Plankton. Plankton owns and operates a struggling restaurant called the Chum Bucket in Bikini Bottom, located just across the street from the wildly popular Krusty Krab, which is owned by his archnemesis, Eugene H. Krabs. The Chum Bucket itself suffers from little popularity. Plankton devotes much of his time and energy to attempting to steal the secret formula of the Krusty Krab's signature dish, the Krabby Patty, hoping that producing the dish will attract customers to his restaurant and put Krabs out of business.

Personality
Plankton is obsessed with attempting to steal the Krabby Patty Secret Formula, knowing that doing it will result in profitability for his restaurant and himself. His numerous attempts to steal the formula and enrich himself has resulted in his gaining a reputation as evil, manipulative, maniacal, and self-centered. What distinguishes Plankton from Krabs is that Plankton focuses less on gaining money, but more on the Krabby Patty Secret Formula, and is outright evil. Krabs, while also manipulative at times and greedy, still has a sense of morality (even though he chooses to ignore it from time to time) and is not outright evil.

Biography
Plankton is currently married to Karen Plankton, a Mark II Surplus UNIVAC computer with 256 GB of RAM.

Plankton makes his first appearance in the season 1 episode "Sandy Goes a-Writin'". Going to Krabby Patty in order to make yet another attempt at stealing the secret formula, Plankton instead encounters SpongeBob, who is distributing fliers in the hope of finding a distributor for Sandy's book The Horrible Condition of Bikini Bottom's Employees, focusing on the "unfair" working conditions of Bikini Bottomites. Plankton agrees to distribute the book, stating that Karen will be able to print it, but then spends a great amount of time attempting to update Karen's hardware and software in order to be able to connect her to the Sheldon J. Plankton P-1 Digital Printer, much to SpongeBob and Sandy's frustration. Plankton is finally able to print copies of the book, which he distributes to the Bikini Bottom Central Department Store, but then SpongeBob and Sandy find out that Plankton has added a preface without their permission, which basically promotes the Chum Bucket over the Krusty Krab. SpongeBob and Sandy go to the Chum Bucket and urge the customers gathered there (having left the Krusty Krab) to see the book as "a plea to help our fellow Bikini Bottomites" rather than "a Chum Bucket propaganda" and tell them that the Krabby Patties are still better than any of Plankton's dishes. They agree and leave the Chum Bucket.