Karen Plankton is one of two major antagonists from the Nickelodeon animated series SpongeBob SquarePants, alongside her husband Sheldon Plankton. She is a talking supercomputer who lives in the laboratory of his restaurant, the Chum Bucket, and is often the one to come up with her husband's plans to steal the Krabby Patty formula, though she is just as quick to make snide remarks at his failures. In the show's earliest seasons, she was rarely seen outside of episodes featuring Plankton, due to only appearing mounted to the wall of his laboratory. Following the release of The SpongeBob SquarePants Movie, in which her mobile body appeared for the first time, she started showing up more frequently, becoming almost as prominent as her husband and the rest of the show's main characters.
Appearances in Christmas specials[]
Karen with Plankton in Rankin/Bass-styled stop-motion animation.
Towards the beginning of the series' stop-motion Christmas special, "It's a SpongeBob Christmas!", Karen suggests to Plankton that he might get a present from Santa if he were not such a jerk. Plankton proceeds to tell her about his plan to turn everyone else in Bikini Bottom into jerks using his "Jerktonium"-laced fruitcake so that he will seem better in comparison. Later, Karen reveals to Plankton that his scheme is flawed because his fruitcake cannot affect SpongeBob, displaying a diagram to explain that SpongeBob's innocence shields his heart from Jerktonium's effects. This inspires Plankton to sabotage SpongeBob's chances of being put on Santa's "nice list" with "Plan B," an evil SpongeBob wind-up toy named ToyBob.
Plankton and Karen in the commercial.
Outside of the show itself, Karen appeared in a 2016 Nickelodeon Asia commercial for SpongeBob apps on sale for Christmas. It features an animation of Plankton and Karen yelling at SpongeBob, Patrick and Sandy caroling.