The Mr. Plankton Universe is an alternate world where Plankton and Mr. Krabs' lives switched. It all started when Karen (real world) suggested to switch life with his life switcher he invented. So Plankton used it and teleported to the Krusty Krab, where Plankton is the founder and owner of the Krusty Krab, while Mr. Krabs is the owner and founder of the Chum Bucket. Mr. Plankton Universe SpongeBob, Squidward, Mr. Krabs, Pearl and Nat Peterson all live in this altered universe.
It was featured in The Algae's Always Greener.