Plankton: 1% evil, 99% hot gas.
~ Karen's scan of Plankton.

Karen Plankton is the secondary antagonist of the Nickelodeon animated television series SpongeBob SquarePants. She is a waterproof computer who lives in the Chum Bucket and is married to Plankton. She and Plankton are constantly scheming to steal the Krabby Patty formula from Mr. Krabs. 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 season 1 episode "Plankton!". In the third season premiere "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 Jill Talley. In the Broadway musical adaptation, she was portrayed by Stephanie Hsu.


Karen is a 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.



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 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 hitman to murder SpongeBob and Patrick. Karen uses her mind-control abilities to enslave the citizens and is one of the only townspeople not to be a slave. This shows that she is just as cruel 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.


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 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.

Villainous Acts

  • "F.U.N.": She tells Plankton how to get the formula by using SpongeBob's trust against him. She also convinces him to get back on track after he starts caring about Spongebob for real.
  • "Plankton's Army": She helps give Plankton the idea to recruit his family members to take down Mr. Krabs.
  • "The SpongeBob SquarePants Movie": In one of her most evil roles, she writes and gives Plankton his most diabolical plan yet: Plan Z, which involves enslaving everyone in Bikini Bottom and sending a hitman to kill SpongeBob and Patrick. She also is the one who mind controlled the citzens. 
  • "Enemy In-Law": She zaps Plankton with a laser after his affair with Krabs' mother.
  • "Friend of Foe": She helps Plankton to try to get the formula by pickpocketing it from Krabs' pocket when Krabs and SpongeBob were distracted.
  • "Krabs à La Mode": She encourages Plankton to steal the formula by using Krusty Krab's frozen state as an advantage because simply freezing the restaurant is not enough to run it out of business.
  • "Plankton's Regular": She paid a random fish named Nat to eat Plankton's chum to keep Plankton from being sad, in spite of the risk on Nat's digestive system.
  • "Single Cell Anniversary": Stealing the Krabby Patty formula as the gift for Plankton in their wedding anniversary. Unfortunately, her undoing in this illegal act was demanding Plankton to give her her own gift, where upon gained what she wanted, Karen was crying so much that she causes her system to overload.
  • "Chum Caverns": Upon discovery of underground cave below Chum Bucket, Karen suggested to used the place's scenery to run the Krusty Krab out of business.
  • "Plankton's Good Eye": She encourages Plankton to steal the formula and aiding him to have a new secondary eye to increase his perception by using SpongeBob's tears. However, Karen's scheme in this backfires as the mutation for creating the second eye resulting unwanted side effect where SpongeBob's persona from that eye began to take over Plankton's mind so she encourages him to despise his good side to restore order on his mind.
  • "Walking the Plankton": Upon discovering that Plankton was too absorbed in his obsession in stealing Krabby Patty due to Krabs intentionally sell patties on the cruise ship that they coincidentally went on board in their honeymoon, Karen was upset so much that she cleaves the ship in two with laser, revealing her surprising capacity to suffer Breakdown Villainous Breakdown in process.
  • "Plankton's Good Eye": She reveals that she loves Plankton's evilness and doesn't want him to become a good guy.
  • "It's a SpongeBob Christmas!": Karen analyzes SpongeBob and finds out that he is immune to jerktonium, leading Plankton to create a wind-up robot sponge to ruin SpongeBob's chances of getting presents from Santa.
  • "Evil Spatula": She unknowingly tries to make faux Krabby Patties out of the recipe SpongeBob gives his talking spatula, which ends up being a trick from Mr. Krabs.
  • "The Legend of Boo-Kini Bottom": She hosts the Chum Bucket's "Horrors of the Krusty Krab" show, which spreads lies about the business practices at the Krusty Krab.


See Also


           Nickelodeon 2009 logo.svg Villains

TV Series
Ren Höek | Angelica Pickles | Ed Bighead | Lars Rodriguez | Miranda Killgallen | Glowface | Tlaloc | Dr. Blowhole | Gart Default | Coverton | Sta'abi | Leslie Noodman | Amanda Killman

Hey Arnold!
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Invader Zim
Almighty Tallests | Zim | Gaz Membrane | Tak | Ms. Bitters | Control Brains | Irken Empire | Mortos der Soulstealer | Iggins | Sizz-Lorr | Santa Claus | Mini Moose

Skrawl | Biclops | Michelle | Beanie Boys | Skrawl's Brain | Quicksand Man | Mr. Wilter | Mrs. Tweezer | The Craniacs | Stinky Witch | Doofi Rudy and Doofi Penny | Boorat | Jacko || Vinnie Raton | Terry Bouffant

The Chump Brothers | Bill Champsley

El Tigre
Sartana of the Dead | Black Cuervo | Voltura | El Tigre | Puma Loco | Lady Gobbler | Dr. Chipotle Jr. | Dr. Chipotle Sr. | Señor Siniestro | Django of the Dead | Golden Eagle Twins | Cactus Kid | El Oso | The Bad Girls | Che | General Chapuza | Comrade Chaos | Silver Wolf | El Tarantula | Ninja Monster Clan | Android El Tigre | Mighty Cheetar

Back at the Barnyard
Nora Beady | Snotty Boy | Phlegmy Boy | Mertin Fargleman | Cave Cow | Goraldo | Don Bling | Aubrey and Max| Snotty Boy's Friends | Inga | Eddie | Bingo | Swimmy | Polly Ivana Sugardaddy | Prunella | Thor | Stinky McStupidhead | Brunhilda | Whiplash McGee | J.T Frittlehoot | Vampire Otis | French-Canadian Crows

The Mighty B!
Portia Gibbons | Gwen Wu | Cherry | Roxxy | Hal | Mr. Griff | Harris Daye | Robot Bessie | K.G. Bianca | Chelsea Gibbons | Chelsea's Friends | Finguere

Fanboy & Chum Chum
Kyle Bloodworth-Thomason | Lenny Flynn - Boyle | Boog Shlizetti | Sigmund the Sorcerer | Marsha | Copy Kitten | Mr. Trick | Berry the Ice Monster | Professor Flan | Necronomicon

T.U.F.F. Puppy
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Rambamboo | Oonski the Great | Biker Ducks | Lava Mole | Giant Bacteria Blob | Breadbots | Emerald Loaf | Commander Conch | Camp Counselors | Pond Monster | Captain Goosington | Hotshot | Poltergoose | Mr. Flutterbee | Freaky Finger Bread | Trash Bandit | Pizza Lord | Zoona and Roni | Bread Foot | Crazy Dentist | P.B. | Ponda Gang | Dishwasher | Ducktor Quazy | Hunch Butt | Robo Toilet 3000 | Rusty | Giant Birthday Cake | Three Headed Birdman | French Chef | Giant Fire Breathing Baby Chick | Giant Underpants | Alley Monsters

The Loud House
Exterminator | Tetherby | Bratty Kid | The Manager | Chandler McCann | Hawk and Hank | Park Ranger | Lindsay Sweetwater | Sue | Petey | Corinne | Street Cats | Steak and Stan Stankco | Michelle and Doug | Lacey St. Clair | The Kitty | S.U.S.P.E.N.S.E. | Carol Linnaeus

It's Pony
Otis Perrybottom | Jill Perrybottom | Bob Perrybottom

Aaaah !!! Real Monsters
The Gromble | Snorch & Zimbo | Simon the Monster Hunter | Jake | Sal


The Amanda Show
Judge Trudy

Drake and Josh
Megan Parker | Thornton Locke | Milo McCreary | Alan Krim

Ned's Declassified School Survival Guide
Billy Loomer | Mr. Sweeney | Harvey Crubbs | Huge Crew | Killer Bees | One-Bite

The Thundermans
Max Thunderman | Dark Mayhem | Green Ghoul | Mike Evilman | King Crab | Lady Web | Scalestro | Son of Scalestrp | Strongdor] | Fairy Pinch-ess | Villain League | Lionel, Jake and Tom | Olympia Wong | Candi Falconman | Darcy Wong | Balfour | Madison Robertson

Nevel Papperman | Lewbert Slime | Nora Dershlit | Chuck Chambers | Mr. and Mrs. Dershlit | Missy Robinson | Amber Tate | Kyoko and Yuki | Chip Chambers | The Petographers | The Shadow Hammer | Francine Briggs | Mr. Howard | Valerie | Jocelyn | Jonah | Rona Burger | Pirates | Marta Trundel | Lervin's Bully | Dimitri and Ivan | Mandy Valdez | Lauren Ackerman | Tessa | Candace | Carter Ford | Steven Carson | Doug Toder | Billy Boots | Cal | Dana Bukowski | The Trick-or-Treaters | Totally Teri Writers | Wade Collins | Natalie | Sunshine Girls | Backflesh

Jade West | Tara Ganz | Hayley Ferguson | Fawn Liebowitz | Mona Patterson | Mr. Dickers | Mrs.Lee | Hope Quincy| Rhoda Hellberg | Melinda Murray| Barney and Billy Triplet | Bella | Christie | Francis Thornesmith | Randy Bronson | Jarold and Merl

Big Time Rush
Mr. Bitters | George Hawk | Wayne Wayne | Rebecca | Ted | Dara's Stepmother | Sandy | Molly | Captain McAlister | Kennedy

Game Shakers
Jimbo | MeGo | Lance

Knight Squad
Sage | Ryker | Commander Umbala | Ryker's Army

I Am Frankie
Lorenzo Bravo | Segundo Mehija | Mr. Kingston | Tammy Gilroy | EGG | Eliza Gaines | Cynthia Mondall | WARPA | Simone | Dóminus | Luz

Welcome to the Wayne
Calliope Organization (Yelena Bishop, Prismal, Masterson, Flowershit)

Are You Afraid of the Dark?
Mr. Tophat | Dr. Vink | Evil Spirit | Adrian | Badge | Basement Demon | Belinda's Witch | Black Figures | Braun Family | Brother Septimus | Chameleons | Corpse | Crimson Clown | Diggers | Doctor Capel-Smith | Evil Executioner | Evil Sheriff | Evil Witch | Ghastly Grinner | Gort | Gremlin | Jake "The Snake" Desmond | Keeper | Koda | Madame Visage | Madeline | Margot | Master Raymond | Mr. & Mrs. Taylor | Mr. Olson | Mrs. Briar | Ms. Valenti | Nosferatu | Peter Kirlan | Phone Police | Renegade Virus | Sandman (Are You Afraid of the Dark?) | Suitmen | Teddy Mars | The British | The Stone Maiden | The Watcher | Zeebo

Henry Danger

The Fairly OddParents
The Fairly OddParents Villains

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Jimmy Neutron Villains

Danny Phantom
Danny Phantom Villains

Spongebob Squarepants
Spongebob Villains

Action League Now!
Hodge Podge | Smarty Pants | Red Ninja | Roboflesh | Big Baby

           NICK Movies.svg Villains

Animated Features
Angelica Pickles | Coco LaBouche | Jean-Claude | King Goobot | Ooblar | Poultra | Alphonse Perrier du von Scheck | Nick Vermicelli | Big Bob Pataki | Sloan Blackburn | Bree Blackburn | Poachers | Siri | Sheldon Plankton | Karen Plankton | Mr. Krabs | Dennis | Cyclops | Victor | Boat Jacker | The Thug Tug Gang | Dag | Nora Beady | Coyotes | Tortoise John | Rattlesnake Jake | Bad Bill | Hawk | Balthazar Douglas Peterson | Maybelle | Ivan Ivanovitch Sakharine | Allan | Tom | Pedro | Falcon | Aristides Silk | Red Rackham | Burger-Beard | Lasombra | Chimpanzombies | Ed Bighead | Zim | GIR | Mini Moose | Gaz Membrane | Almighty Tallests | Irken Empire | King Poseidon

Live-Action Movies
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See Also
Avatar Villains | Danny Phantom Villains | Henry Danger Villains | Invader Zim Villains | Jimmy Neurton Villains | Lemony Snicket Villains | SpongeBob Squarepants Villains | The Fairly OddParents Villains | TMNT Villains

           SpongeBob.png Villains

Main Villains
Mr. Krabs | Plankton | Karen Plankton | Mrs. Puff

Major Villains
Flying Dutchman | Man Ray | Sinister Slug | Jumbo Shrimp | Atomic Flounder | Dirty Bubble | Bubble Bass | Plankton Family | DoodleBob

Movie Villains
The SpongeBob Squarepants Movie:
Mr. Krabs | Mrs. Puff | Plankton | Dennis | Karen Plankton | Victor | Cyclops | Boat Jacker | The Thug Tug Gang
The SpongeBob Movie: Sponge Out of Water:
Plankton | Mr. Krabs | Burger-Beard
The SpongeBob Movie: Sponge On the Run:
Plankton | Mr. Krabs | Karen Plankton | King Poseidon

Other Villains
Every Villain Is Lemons | Abrasive SpongeBob | Alaskan Bull Worm | Puffy Fluffy | Sergeant Sam Roderick | Tattletale Strangler | Lord Poltergeist | Carl | Big One | BlackJack SquarePants | Evil Alien Jellion Overlord | Sea Bear | The Moth | Hash-Slinging Slasher | Con Man | Master Udon | Evil Syndicate | King Gorge | The Mawgu | Don Grouper | Animatronic Hieronymus Glove | Gordon | Coupe | Triton | The Fisherman | Madame Hagfish | Dead-Eye Plankton | Art Appraiser | Miss Gretel Puss | Planktonamor | Dreaded Patrick | Karen 2.0 | Captain Scarfish | Dragon Jellyfish | The Jellions | SpongeBot SteelPants | Robot Plankton | Robots | Globulous Maximus | Flats the Flounder | ToyBob | Cuddle E. Hugs | Gale Doppler | Mini Doodles | Plankrab | Doctor Negative | Jelliens | Seymour Scales | Catfishstress | Octopus King | Swamp Natives | Hoodoo Guru | Earworm | Krabby Patty Zombies | Plankton's cellmates | Alternate Reality Mr. Krabs

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