Sheldon James Plankton is an antagonist in the SpongeBob SquarePants series. He operates a struggling restaurant called the Chum Bucket alongside his computer wife Karen. The Chum Bucket is located directly across the street from the Krusty Krab. Plankton and Karen often devise schemes to steal the Krabby Patty recipe and put Mr. Krabs out of business. Plankton succeeds at stealing the recipe in the movie, but his goal of world domination is thwarted by SpongeBob.


Plankton has spent a long period of time trying to destroy the Krusty Krab, a franchise owned and operated by his nemesis, Eugene Krabs. The two used to be close friends back in grade school, but as revealed in "Friend or Foe", a dispute over the Krabby Patty recipe ended their friendship. During this time, Plankton was dating Karen, who was only a security system at the time. He would later upgrade her into an evil computer and analyzer to help out with his schemes to steal Krabs' formula. Plankton is incredibly intelligent and is able to build advanced robots, but nonetheless his plans always seem to fail in the end.

Early life and career

Plankton's best friend from birth was his future rival Eugene Krabs. This history was revealed in "Friend or Foe". Both Krabs and Plankton were considered outcasts by other children, because Krabs was poor and Plankton was a nerd. When they discovered that money could bring them out of their poverty, they decided to make money selling hamburger patties, and set up a mini restaurant in the local dump. At first, their burgers were not successful. the first of their patties was tried by Old Man Jenkins, who was knocked out by the contaminated burger. Plankton started complaining about how Jenkins had been old and not able to handle the patty. Krabs, offended by this, tried to take the recipe from Plankton to improve upon. Plankton wanted to do this himself, but only ended up with the corner of the recipe which read "and a pinch of chum". Plankton stormed out of the restaurant, and went to create his own recipe using only his memory,the corner of the recipe, and science. At school, Plankton attempted to sell his chum burgers in a chum bucket and failed, when Krabs succeeded with his Krabby Patties, which he had created by accident when Plankton had slammed the door. Ingredients fell in the patty batter, thus creating the patty. Plankton later named his restaurant the Chum Bucket, after the secret ingredient of the original unsuccessful patty recipe. Mr. Krabs named his restaurant The Krusty Krab. To this very day, Plankton has been single-mindedly obsessed with obtaining the Krabby Patty formula and running the Krusty Krab out of business, often going to incredible and often ridiculous lengths to do so; in "SpongeBob's Last Stand", for example, he builds a massive highway that goes straight through Jellyfish Fields and over the Krusty Krab leading right to his restaurant simply to do so.

In "Dunces and Dragons" it is implied that the Plankton/Krabs feud began centuries ago when Plankton's evil overlord ancestor Planktonamor was vanquished by a Krabby Patty. Since there is not any feud between Krabs and Plankton in their early childhood, it is possible that these families settled their differences until the childhoods of Krabs and Plankton.

In a comic story, Krabs and Plankton are shown to have been college roommates. Their rivalry is shown to have been caused by a series of things, including Plankton being stepped on by Mr. Krabs (which did not annoy him at all), being closed inside Mr. Krabs' book (which aggravated him a little) and Mr Krabs going out with his date and Plankton's date (which started their rivalry). Since it was revealed in "Friend or Foe" that they were rivals earlier than college, this story is likely non-canon. Even in the present day of the series, Krabs and Plankton are occasionally shown to somewhat get along, such as in "New Leaf" and "Best Frenemies".

Plankton's restaurant, the Chum Bucket, has always been extremely unsuccessful, not only because of competition from the Krusty Krab and Plankton's rude and cruel treatment of the people in Bikini Bottom, but also due to the extremely poor quality of the food and Plankton's constant failure to clean the place up. As its name implies, the Chum Bucket serves chum-based foods, all of which taste terrible. In "Plankton's Regular", the Krusty Krab adds chum to its menu in an attempt to steal Plankton's single regular customer (who was in reality being paid by Karen to eat at the Chum Bucket and pretend to like the food there). The customer is disgusted by their chum, and says that it is the second foulest thing he has ever tasted (it can be inferred that Plankton's chum is the number one worst). This implies that chum is inherently disgusting, and cannot be made to taste good, although is shown to be false in the Season Seven episode, "Greasy Buffoons". Plankton used excess grease from the Krusty Krab's grease trap that was dumped near the Chum Bucket to make his sales skyrocket (although it is unknown if this made the chum taste good, as Plankton could have been lying, and his customers could have been tasting only the grease, as the flavor could have covered up the chum's flavor).

It should be noted that in real life, chum is made of grounded up fish parts that are inedible to humans, such as heads and guts, and is used as bait for sharks and similar creatures. This would mean that Plankton is killing fish (or at least collecting dead fish) and serving their remains to other fish. This has only ever been touched upon in "The Krabby Kronicle", where SpongeBob prints a story claiming this. However, SpongeBob was being tricked by Mr. Krabs into printing absurd lies to appeal to customers, and this story was supposedly false. It also possible, that in the alternate reality the show takes place in, chum might be made of something completly different (although still likely disgusting), like in the episode Spongicus, Plankton named of many werid things that make up his chum, and fish parts was not on the list.

Plankton has no regular employees, and runs the Chum Bucket entirely by himself, although he spends most of his time in his laboratory, due to having no customers. Plankton actually runs the restaurant only when he has potential customers. Also, when he does have customers, he also uses artificialy intelligent machines to cover the other positions.

Although it has been stated on multiple occasions that Plankton has never had a single customer, he has on several occasions had brief success, particularly in more recent episodes, such as "Spongicus" and "Chum Caverns".

[1]Plankton's home, known as the Chum Bucket.Added by AMK152


Plankton and Karen have been married for a long time and started dating in grade school. They love each other very much, but their relationship has had troubles over the years, usually as a result of Plankton's arrogance. The Plankton family has included marriages between plankton and technology for generations, as shown in the special "Dunces and Dragons," where Plankton and Karen's ancestors (Planktonamor the wizard and Karen the crystal ball) appear. Being a microscopic organism, Plankton's biological family numbers in the thousands. In "Plankton's Army", he recruits his entire family to help him steal the formula, thinking them all to be criminal masterminds like himself. However, much to his surprise, his family consists entirely of uneducated, red-necked hillbillies. These Relatives include (but are not limited to): Clem Plankton, Zeke Plankton, Rufus Plankton, Jeke Plankton, Billy Bob Plankton, Billy Jim Plankton, Billy Billy Bo Willy Banana Fanna Fo Filly Plankton, Doug Plankton, Ennis Plankton, and Rainchild Plankton, the only ones named.

Plankton has two known ancestors. One is the evil wizard Planktonamor, who lived during medieval times and appeared in "Dunces and Dragons". Another is Dead Eye Plankton, a wealthy citizen who attempted a hostile takeover of Bikini Gulch but was defeated by Sheriff SpongeBuck SquarePants. Dead Eye Plankton lived during the Wild-West era and appeared in "Pest of the West".

Video Games

Plankton appears in virtally all SpongeBob-related video games, usually as a major antagonist.

  • In SpongeBob SquarePants: Battle for Bikini Bottom, Plankton devises a plan to take over Bikini Bottom and obtain the Krabby Patty formula by creating a robot machine called the "Duplicatotron 3000". However, the robots do not obey him and begin mindlessly rampaging across Bikini Bottom, because he forgot to set the switch from "Do not Obey" to "Obey". Plankton convinces SpongeBob and friends to defeat the robots, as SpongeBob believed the situation was his fault, so that he can have enough time to fix the main Duplicatotron 3000 so he can take over the city be controlling the robot army.
  • In The SpongeBob SquarePants Movie Game, Plankton is the main antagonist, reprising his role from the movie.
  • In SpongeBob SquarePants: Lights, Camera, Pants!, Plankton appears as a playable character. In the game, he uses a robotic suit to act in the auditions (the parts that are played). Also, the "Captive" role, as well as the auditions for it, take place in the Chum Bucket.
  • In Nicktoons Unite!, Plankton is one of the four main villains of the game. He uses a crab mech to fight the heroes.
  • In SpongeBob SquarePants: Creature from the Krusty Krab, Plankton is one of three playable characters, as well as the final boss of the game. He enlarges a Krabby Patty to massive size, only to have it come to life and begin chasing him. Eventually, Plankton enlarges himself to gigantic size, and begins rampaging across the city in pursuit of the giant patty. He is eventually defeated and reverted to his original size by Patrick.
  • In SpongeBob SquarePants: SuperSponge, Plankton has a brief cameo, in which he yells at SpongeBob for stealing his time machine. "Blast you SpongeBrat! You have found my secret time machine! Well whatever you do, make sure you fill it up before you bring it back!"
  • In SpongeBob SquarePants and Friends in: Globs of Doom Plankton and 4 other villains team up with the heroes to defeat Globulous.
  • In Nicktoons Racing Plankton appears as an unlockable character.


  • Hypno-Pod: Hypnotizes jellyfish to be slaves as seen in the online game, Plankton's Pernicious Plot.
  • Time Machine: Seen in SuperSponge
  • Mind Control Bucket Helmets:Control's the mind of fish and turns them into Plankton's slaves.Seen in "The SpongeBob SquarePants Movie."
  • High-Powered Mechanical Bio Arm: Opens anything - revealed but malfunctioned in the episode, "Best Frenemies."
  • Enlargetron: Makes things bigger, seen in Creature from the Krusty Krab.
  • Robo-Krabs: Robot version of Mr. Krabs, Seen in Imitation Krabs, Operation Krabby Patty, New Leaf, and Spy Buddies.
  • The switch-lives-just-to-know-what-it's-like-o-microfier. Seen in "The Algae's Always Greener".
  • New computer inventions, seen in "Komputer Overload". {}the dispictulator: a freeze ray plankton used in Creature from the Krusty Krab.
  • Brain-Powered Sponge-Robot: A robot modeled after SpongeBob that runs on brains.
  • K.A.R.E.N.: Robot Computer/Wife that can analyze anything. She is mobile. She can also create holograpic food.
  • Pat-Bot: Built with a paddle ball, pogo stick, razor blade, and metal claws.
  • Many more shown throughout the series.
  • Duplicatotron 3000: A machine that creates seemingly endless amounts of robot soldiers. Seen in SpongeBob SquarePants: Battle for Bikini Bottom.


Plankton is afraid of whales, enough to go insane.

  • Reason: A pod of whales ate his ancestors. (also because whales eat plankton)


Main Article: List of Plankton's Plans


  • A running gag is that in many episodes he appears in (including the movie), he gets squished.
  • It is revealed in one episode that Plankton is not actually green, his outfit is. Karen removes the green and we see an underwear clad pink plankton embarrased of his nakedness. He also has a rack with identicle green suits.
  • Plankton is left handed.
  • Plankton appears in the "United Plankton Pictures" logo.
  • Interestingly, although his name is "Plankton," he bears more resemblance to the real-life class of Organisms, Copepoda (Cyclops), which feed on phytoplankton. Do note that plankton are known to come from a different Kingdom than Copepods.
  • Despite all of Plankton's schemes, he has only been arrested two times, in The SpongeBob SquarePants Movie and Krabby Road. (He escaped from the cops in Goo Goo Gas).
  • Plankton should be able to remember the Krabby Patty Secret Formula from The SpongeBob SquarePants Movie, although Stephen Hillenburg said that chronoligacially, The SpongeBob SquarePants Movie is the last part of the series. And also, he could have been in jail for long enough to forget and want to get the formula again.
  • He was called "Shelly" in The Last Stand.
  • Plankton is college educated, which has become a running gag throughout the series, as he would usually shout, "I went to college!!!!!!!!!!!!!" while pointing at his eye as a pun when Mr.Krabs foiled him.
  • Plankton is afraid of Whales in the episode where Krabs dresses up like his daughter but not in the episode where Plankton switches lives with Mr. Krabs.
  • Out of his whole family, he seems to be the smartest, as his family is shown to be quite clueless and unintelligent.
  • His family is made up of hillbillies (or what they appear to be), and he appears to have forgotten their stereotype after all these years, as in their episode, he believes they are "criminal masterminds" and when he sees them, he is shocked and says "I've been away from home longer than I thought." It is possible that after this, he was disgusted by their stupidity, and possibly taught them to be smarter.
  • His real name is mention on Plankton's Army.
  • According to the TV movie Truth or Square, Plankton has made a thousand and three failed attempts to steal the formula.
  • At 2 inches tall, Plankton is actually gigantic for his kind. They, of course, did that to make viewers see him on the screen.
  • Plankton actually should be half the size of SpongeBob, as SpongeBob is four inches tall.
  • In Plankton!, Plankton has a lab, which is just a real Labrador.
  • In later episodes, when Spongebob holds Plankton in his hand, he is bigger or Spongebob's hand is smaller (compare Plankton! with Single Cell Anniversary or The Main Drain).
  • In The Main Drain, Plankton is unusually bigger than other episodes.
  • He and Mr. Krabs is the only in their family to ever make friends with each other, their predecesors are enemies.
  • In several relatively recent episodes, the inside of his mouth was purple. But that was corrected back to red in later episodes.