Plankton

Sheldon J Plankton is the main antagonist of the show SpongeBob SquarePants.

Biography
Plankton is the owner of the chum bucket. he is married to computer named Karen.

Personality
Plankton is evil, cruel but sweet and smart. he fears whales and has a rivalry with Mr. Krabs (though they work together in Battle of the Multiverse).

Criminal Records
Plankton has an expansive history of committing felonies and misdemeanors, all while attempting to obtain the Krabby Patty recipe and outnumber Mr. Krabs' business. He has been arrested five times: in The SpongeBob SquarePants Movie, "Krabby Road," "Sweet and Sour Squid," "Fiasco!," and "Call the Cops." Plankton's criminal record includes, but is not limited to:
 * Aiding in crime: In "Jailbreak!" his chum is used by criminals as knockout gas and disguises, both for robbery.
 * Dealing with Patrick: In "Spongicus," Plankton arranges for Patrick to be eaten by a group of lions for the entertainment of others.
 * Hiring an agent: In The SpongeBob SquarePants Movie, to prevent SpongeBob and Patrick from making it to Shell City, Plankton hires an agent by the name of Dennis to deal with the duo. Dennis is eventually hit by a boat.
 * Attempted theft: In most of his major appearances, Plankton makes an effort to obtain the Krabby Patty formula, with his plans usually backfiring on him in the end. He gets arrested twice for doing this in "Krabby Road."
 * Breaking and entering: Plankton breaks into SpongeBob's house in "Plankton!" to enter his brain. He also invades Patrick's house in "Salsa Imbecilicus" to get a copy of his DNA.
 * Disturbing the peace (falsely accused): In "Sweet and Sour Squid," Plankton is arrested for playing clarinet that caused a disturbance throughout town, even though it is Squidward's fault.
 * False identity: Plankton has disguised himself under many fake identities so as to deceive others and obtain the formula; he uses the identity "robot game show host" in "Imitation Krabs" and "Cashina Krabs" in "Married to Money."
 * Framing: In the first movie, Plankton accuses Mr. Krabs of stealing King Neptune's crown so as to get him executed and thereby finally succeed in stealing the formula.
 * Deception: Plankton has engaged in many unusual acts of kindness in the name of personal gain: In "F.U.N.," Plankton pretends to be in a friendship with SpongeBob so as to obtain the formula from him. In "Walking Small," Plankton deceives SpongeBob in believing that berating the beach attendants is done with kindness so he can make an unauthorized development to the property. In "New Leaf," Plankton claims he's changed his ways and showcases that through turning the Chum Bucket into a gift shop, but this was really just a way of deceiving Mr. Krabs. In "Krabby Road," Plankton forms a band with SpongeBob, Patrick, and Squidward with the intent to obtain the secret formula.
 * Grand theft of royal property: Plankton steals King Neptune's crown in the first movie and sells it to Shell City without his consent.
 * Identity theft: Plankton has used many people's identities to steal the formula, namely, Mr. Krabs in "Imitation Krabs," Sandy in "Someone's in the Kitchen with Sandy," SpongeBob's great grandmother in "Gramma's Secret Recipe," and Gary in "Shellback Shenanigans."
 * Lying under oath: In "Krabs vs. Plankton," Plankton fakes his injuries in an attempt to sue Mr. Krabs.
 * Practicing without a license: As a means of deception, Plankton has posed under many job titles without having the license required or official permission to hold such occupations; he impersonates a therapist in "Fear of a Krabby Patty," a salesman in "Shellback Shenanigans," and a Girl Scout in "Pineapple Invasion."
 * Prison escape: Plankton escapes from jail in the episodes "Krabby Road" and "Jailbreak!"
 * Bikini Bottom take-over: In the video game Battle for Bikini Bottom, Plankton creates a spade of robots to vandalize and threaten Bikini Bottom to increase his possibility of stealing the formula. In The SpongeBob SquarePants Movie, Plankton brainwashes the citizens into worship him; once SpongeBob frees all the citizens from the bucket helmets, the police discover his motive and deal with him. In "Chum Caverns," Plankton enslaves a group of cave dwellers.
 * Taking advantage of others: When Plankton enslaves Bikini Bottom in the first movie, he forces Gary to pull a several-ton block of stone. In "Walking Small," Plankton uses SpongeBob for unauthorized land development and manipulates him into following his orders, deceiving him in believing that they are acts of kindness.
 * Theft: In The SpongeBob SquarePants Movie, he finally gets a hold on the Krabby Patty formula. He also steals Sandy's fur pelt in "Someone's in the Kitchen with Sandy" and--albeit unintentionally--a piece of famous art in "Fiasco!," the latter instance of which lands him in jail with Squidward.
 * Treason and crimes against humanity: In the first movie, Plankton acts disloyal to the king of Bikini Bottom by stealing his crown and eventually enslaving him with a mind control helmet. Additionally, he betrays the town of Bikini Bottom by renaming it to suit himself and making the city revolve purely around him.
 * Violation of food safety laws: Plankton has poisoned his customers with his chum in numerous episodes, such as in "Plankton's Regular," "Spongicus," and "For Here or to Go." In "Friend or Foe," he and Mr. Krabs poisoned Old Man Jenkins with their Plabs Patties.

Trivia

 * Plankton seems to be friends with King Dedede.
 * Plankton has been Giant Multiple times.
 * Plankton is usually Eggman's partner, This is likely because they share the smart IQ.