Chum Bucket

The Chum Bucket is Plankton's place of business, located directly across the Krusty Krab. Unlike the Krusty Krab, the Chum Bucket is usually devoid of customers, as chum is considered disgusting by just about every single citizen of Bikini Bottom (even Plankton himself; in the episode, "Chum Bucket Supreme", he is seen only pretending to eat Chum Stick in order to attract a potential customer). Menu items are all chum-based, which include Chum-balaya, Chum Nuggets, and Chum Sticks. The Chum Bucket also serves as Plankton's home, where he lives with his computer wife, Karen. Plankton tries to steal Krabby Patties or the secret formula from the Krusty Krab to get customers and drive the Krusty Krab out of business. He usually fails, except in in The Spongebob Squarepants Movie; with Mr. Krabs frozen solid by King Neptune (having been framed by Plankton for the theft of King Neptune's crown), Squidward unconcerned, and Spongebob out with Patrick trying to recover the stolen crown from Shell City, Plankton at long last succeeds in stealing the Krabby Patty recipe, and the Chum Bucket sees long lines of customers.

There have been other instances where the Chum Bucket has been successful, although not for long (and without stealing the Krabby Patty recipe). In "Plankton's Regular", Nat visited the restaurant daily, each time eating a Chum Stick. However, it was later revealed that Nat was only eating at the Chum Bucket because he was paid to do so by Karen, who was tired of hearing Plankton's complaints of having no customers. Nat could no longer continue to uphold his end of the deal, as his body couldn't take the food anymore. In "Chum Caverns", Plankton's plan to dig under the Krusty Krab goes awry and he uncovers an underground cave. He manages to attract customers by charging them admission, and while down there, they dine upon Chum Bucket fare. In "Chum Bucket Supreme", Plankton hires Patrick to create a catchy slogan that will lure customers. Patrick comes up with the phrase, "Chum is Fum", which attracts customers. However, when the phrase becomes stale, people start to leave. Patrick comes up with another phrase, "Fum is Chum" (the same phrase, only with the words Chum and Fum switched). This lures the customers back. Patrick resigns, but when Plankton insults his customers (while accidentally standing on the intercom), he loses them all. Patrick is then seen pitching his phrase ideas to the Krusty Krab, which has the new slogan "Krabby Patties Are Fum".

Plankton's decision to sell chum is the result of Plankton and Mr. Krabs fighting their original recipe a long time ago, as seen in "Friend or Foe". They made their own recipe for a burger, but it was a flop as their first customer, Old Man Jenkins, fell ill upon eating it. This resulted in an argument between Mr. Krabs and Plankton, and in the process, the recipe was torn in half. While Mr. Krabs received most of the recipe, Plankton received the bottom half, which read "and a pinch of chum". Despite the recipe asking for "a pinch", Plankton sells foods made entirely out of chum.