169b - Planet of the Jellyfish

It starts out as a happy day for jellyfishing. SpongeBob and Patrick are catching jellyfish when SpongeBob says that if they wouldn't sting, they would be perfect pets. A large alien jellyfish-like monster with large black eyes consumes a jellyfish, and then out of one of the tentacles spits a small pile of pink goo, which morphs into a jellion, a jellyfish with large black eyes. Jellion #1 is commanded to engulf someone as the Jellion King spits out more jellions. Patrick goes to take a nap, with Jellion #1 following him. As Patrick naps, Jellion #1 stretches out its body so that Patrick is inside of it, then one of its tentacles spits out a tall pile of pink goo, with morphs into Jellion Patrick, which is Patrick but with large black eyes, same as the Jellion. Patrick uses his blue mouth tentacles to pick up his net as SpongeBob catches Jellion #1. Jellions swarm into Jellion Patrick's net, and then Jellion Patrick gets an idea to give his jellions to everyone in town.

Later, SpongeBob and Jellion Patrick arrive at Squidward's house. Jellion Patrick stuffs his last jellion into Squidward's mail slot, then 1 second later, the jellion's tentacle spits out a tall light blue pile of goo from the window, which morphs into Jellion Squidward. Jellion Squidward and Jellion Patrick wish SpongeBob a good night. SpongeBob sleeps cozily in his bed, as Jellion #1 attempts to consume him, but SpongeBob awakes, with insomnia. As he watches a late movie, Jellion #1 tries again to consume him, but SpongeBob throws popcorn into Jellion #1's mouth. Jellion #1 starts choking on the popcorn, falling behind the couch.

The next morning, SpongeBob puts Jellion #1 into a cage as he leaves for work. Jellion #1 escapes, and consumes Gary as he sleeps next to a plant and the plant. His tentacle spits out another small pile of goo, which reveals a Jellion Gary-plant hybrid. The scene switches to the Krusty Krab, 99% filled with Jellion Bikini Bottomites, except for one man. The jellions order Krabby Patties "hold the mayo" until the guy who wasn't a Jellion orders a Krabby Patty with extra mayo. Jellion Mr. Krabs comes and says that they were out of the condiment called mayo, and he places a jellion on the guy's head. SpongeBob thought that was weird, because the Krusty Krab had a fresh wall of mayo in the freezer. SpongeBob told Jellion Patrick (who was operating the grill) that he was getting mayo for the guy's patty. Patrick turned his head around, his torso still facing the grill, and his mouth tentacles consumed the patty. SpongeBob went to the freezer and grabbed a box of mayo, then he looked through the peephole. It showed everyone in town, minus Sandy, hibernating in transparent green cocoons hanging from the ceiling, as the Jellion King commanded his jellions (on either side of him) to do stuff for him.

SpongeBob realized that something was very wrong. SpongeBob was ordered by Jellion Mr. Krabs to take a nap. SpongeBob flees from the Krusty Krab, with several Jellion Bikini Bottomites chasing him. SpongeBob is captured and kidnapped by Sandy. Sandy tickled him, and he giggled, showing he wasn't a jellion clone. They figured out that the weakness was mayo, since Jellions ordered food with no mayo. They then exited with sunglasses with lens that looked like jellion eyes. Unfortunately, when joking in front of Jellion Mr. Krabs, SpongeBob elbowed Sandy, knocking off her sunglasses, and Jellion Mr. Krabs shouts "IMPOSTER," which knocked off SpongeBob's glasses. SpongeBob quickly grabbed a mayo sprayer and destroyed the entire town of Jellion clones. When a clone was destroyed, the real person of the clone awakened, and the cocoon disintegrated.

SpongeBob and Sandy find the hideout, containing every Bikini Bottomite cowering in fear. SpongeBob destroyed one side of the Jellion King's jellions, but then the mayo started to freeze. SpongeBob tossed the mayo from the jar, but it froze and landed in between the Jellion King's eye stems. Sandy turned up the heat, and the mayo melted, destroying the Jellion King. The remaining several Jellions, not hit by mayo, then pop like bubbles. SpongeBob explained everything, which took eleven minutes. Patrick tastes the jelly and compliments it as relish. Soon, the goo remaining from the clones and jellions was sold as Evil Clone Jelly Relish for $4 extra than regular Krabby Patties. Patrick then orders a Krabby Patty with Jelly Relish, and then says "Hold the mayo." SpongeBob hears this and looks suspiciously at Patrick, and then the words "The End?" appear on the screen, ending the episode.