Karen Plankton

Karen Plankton is one of the main villains of the SpongeBob SquarePants television series and its theatrical films, along with her husband Sheldon J. Plankton (Douglas Lawrence). She is a self-aware A.I. who is Plankton's sidekick and serves as the main computer system of the Chum Bucket laboratory. She and Plankton are constantly scheming to steal the Krabby Patty formula from her husband's archenemy Mr. Krabs (Clancy Brown). Karen is typically the brains of the operation, coming up with complex plans to run Krabs out of business. However, Plankton has a tendency to take all of the credit for her ideas. Karen and Plankton first appeared in the episode "Plankton!" from season one. In the third season opener "The Algae's Always Greener", it was revealed that Karen is Plankton's wife. Since then, many episodes focusing on the Planktons have involved their marriage. She is voiced by Jillian Talley, who also voiced Nina Neckerly, Ms. Mucus, and Gretchen the Alligator in Camp Lazlo (2005-2008).

Biography
Karen is Mark II Surplus UNIVAC with 256 gigabytes of RAM. She was built by Plankton himself out of a calculator, a mass of wires, and a security system. They first met and dated before Plankton became evil. The further depth of Karen's early life is debatable, since she has two parents. This was first hinted when Plankton told her, "Your parents must have been like, part computer or something." In Single Cell Anniversary, Karen's AI mother is revealed to be a software program named EMILP. Her father is an outmoded computer named Fredrick, who has so far only been seen in an issue of Nickelodeon Magazine.

Personality
Karen normally acts like a nice and loving person when she and Plankton are in a good mood, but she is also evil enough to be a villain (possibly more so than Plankton). In The SpongeBob SquarePants: The Movie, it is shown that Plankton has a filing cabinet of evil plans that Karen reminds him about. Since she writes the majority of his plans, it can be assumed that she wrote these as well. They are in a descending order from harmless to sinister, the worst being "Plan Z" — the only scheme to result in Plankton successfully stealing the formula and using it to his advantage. This plan involves enslaving everyone in Bikini Bottom, forcing a frozen Mr. Krabs to watch the town descend into evil and be killed by King Neptune, and sending a hit man named Dennis to kill both SpongeBob (Tom Kenny) and Patrick (Bill Fagerbakke). Karen uses her mind-control abilities to enslave the residents and is one of the only townspeople not to be a slave. This shows that she is just as cruel, wicked, malicious, and sinister as her husband, if not more.

Her darkest side is also shown in "Plankton's Good Eye" where she encourages Plankton to be evil and hates his good side. Other instances of her dark side include using her lasers on Plankton in multiple episodes and assisting him in his plots in nearly every story focusing on them.

Appearance
Being an AI, Karen usually manifests on the large-screen computer in Plankton's lab where she has green facial features. Her face is mostly depicted in the form of a wavy green line. However, she has many other forms since Plankton builds her system into most of his inventions. Her other most common form is a robotic body designed to look like a portable wheeled computer with detachable robot arms that made its debut in SpongeBob SquarePants: Friend of Foe. Oddly, when sprayed by Plankton's baby gas (a special gas that reduces people to a baby version of themselves) she was reduced into a calculator.