Karen Plankton is one of two major antagonists from the Nickelodeon animated series SpongeBob SquarePants. She is a talking supercomputer who lives in the Chum Bucket laboratory and gives her husband Sheldon Plankton plans to steal the Krabby Patty formula.
Appearances in Christmas specials
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 wish to turn everyone else in Bikini Bottom into jerks using "Jerktonium"-laced fruitcake. This way, he will seem better in comparison. Later on, Karen reveals to Plankton that his scheme is flawed in that his fruitcake cannot affect SpongeBob. Karen's screen displays a diagram to explain that SpongeBob's innocence shields his heart from Jerktonium's effects. This inspires Plankton to sabotage SpongeBob's chances of getting a present with "Plan B," an evil SpongeBob wind-up toy.