Karen

Karen Plankton is a character in the animated television series SpongeBob SquarePants, a waterproof supercomputer and Plankton's wife. Along with Plankton, Karen is one of the two main villains of the series.

It comes in two main forms: a large wall-mounted monitor or a portable computer on wheels.
In both forms, it is primarily a black screen with a blue border and a neon green line that moves when she speaks.
The posable form is equipped with removable robotic arms, which have been almost always present since the tenth season.

First appearance: In the episode "Plankton!", Karen is used as part of Plankton's analyzer and does not speak to him. Her role is expanded in the episode "Fun," where it is revealed that she is sentient and supports Plankton in his mission to steal a Krabby Patty.
Name: Karen is named after Karen Hillenburg, the wife of series creator Stephen Hillenburg.
Originally: Plankton installed Karen as a security system at the junkyard.
Along with her role as co-owner of the Chum Bucket, Karen works as a cook and cashier, but she rarely gets to actually perform these tasks due to the restaurant's unpopularity.

It has many human-like qualities: it talks, cooks food, and expresses various emotions, which makes it very different from a regular robot or computer.
Many of the ideas for stealing the secret Krabby Patty recipe belong to her, although Plankton often takes credit for them, for which Karen resents her husband.
Karen has a built-in laser weapon, which is first shown in the episode "Born into the Enemy."
Karen has a program called P.E.V.T. (Mother-in-Law Emergency Intervention Program) - when something happens to Karen, this program automatically loads up in the form of Plankton's mother-in-law, who dislikes her son-in-law.

An intelligent, analytical person.
She cares about Plankton more than anything in the world, almost everything she does is to help him.
She loves Plankton for his evilness. This is evident in the episode "Plankton's Good Eye," in which Karen is horrified when Plankton inadvertently begins to abandon his evil ways after growing a second eyeball.
Karen has no interests or hobbies of her own - she was created as a wife.