Karen Plankton

Karen is Plankton's wife. A Mark II UNIVAC, she is the main computer system of Plankton's lab, and is often the source of his plots. She is voiced by Tom Kenny's wife, Jill Talley. When they got married, Karen Plankton. Karen usually manifests on the large-screen computer in Plankton's lab, but sometimes acts through a portable wheeled computer. She was first shown in the episode "Plankton!", although in her first appearance she was simply Plankton's talking computer and would not be established as his wife until later on. Karen and Plankton's relationship is a very troubled one. Plankton sometimes does not consider her his true soulmate, and in one episode explains to her that W.I.F.E. stands for "Wired Integrated Female Electroencephalograph". The two frequently argue, and Karen is often very bossy and rude to her husband, having nagging software installed in her. She also thinks Plankton's first name is funny, as shown in "Plankton's Army". Karen is often indifferent to her husband's plots to defeat Mr. Krabs and often shows very half-hearted dedication to his plans for domination over others. Despite their differences, Plankton has said that marrying Karen was the greatest thing that ever happened to him, the second being his Evil Plan Z succeeding. Unlike Plankton, however, Karen shows some degree of dedication for her husband. This is evident whenever she appears, often showing it in the form of assistance in Plankton's schemes, consoling him whenever he's down, and even crying upon Plankton when he told her what W.I.F.E. stands for. It is most likely that Plankton either ignores, or cannot register the acts of kindness that Karen often performs for him, resulting in their various feuds.
Karen is, in some ways, smarter than her husband. A running gag in the series is that while Plankton is contemplating his plans in his lab, Karen will suggest a route of action to him, and he will either not heed her plans or take credit for them.
Karen is a Marc 2 Surplus UNIVAC with 256 gigabytes of RAM, and it has been mentioned that she was a security system before marrying Plankton. In "Goo Goo Gas", when Plankton sprays her with the gas, Karen is turned into a calculator. In "All That Glitters", a monitor that looks exactly like Karen in her portable form is seen in the hospital, and in Shellback Shenanigans he mistakes it for Karen.
In the episode "Single Cell Aniversary" it appears she has an "Emergency Mother-in-law Program," or E.M.I.L.P. for short. She also says that Plankton will someday find the secret formula to the Krabby Patty.