- SpongeBob SquarePants
- Sandy Cheeks
- Patrick Star
- Eugene H. Krabs
- Squidward Tentacles
- Gary the Snail
- French Narrator
- Jelliens (debut)
- Jellien Leader (debut)
- Fred (blue)
- Martha Smith
- Peterson Nat Tucker
- Billy (lime fish)
- Jimmy Gus
- Harold Bill Reginald Scott (known as "random guy")
- Tom (cameo)
- Frank (red shirt)
- Norma Rechid
- Nathiel Waters
- Frankie Billy
- Ivy (gray)
- Frank (red shirt)
- Frank (lifeguard)
- Orange fish (debut)
- Jellien clones (debut)
The episode starts out with SpongeBob and Patrick catching jellyfish at Jellyfish Fields when the latter says that if they would not sting, they would be perfect pets. Shortly after, 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 jellien, a jellyfish with large black eyes. Said jellien is commanded to engulf someone as the Jellien King spits out more jelliens. Patrick goes to take a nap, with the jellien following him. As the former naps, the latter 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 Jellien Patrick, whom is Patrick but with large black eyes, same as the jelliens. Patrick uses his blue mouth tentacles to pick up his net as SpongeBob catches the jellyfish. Jellies swarm into Jellien Patrick's net, and then Jellien Patrick gets an idea to turn everyone in town into jellien people by giving them jelliens.
Later at night, SpongeBob and Jellien Patrick arrive at Squidward's house. Jellien Patrick stuffs his last jellien into the latter's mail slot, then the jellien's tentacle spits out a tall light blue pile of goo from the window, which morphs into Jellien Squidward. This jellien and Jellien Patrick wish SpongeBob a good night. The latter sleeps cozily in his bed as the Jellien that originally captured Patrick attempts to capture him, but SpongeBob awakes with insomnia. As he watches a late movie, the jellien tries to capture him again, but SpongeBob throws popcorn into the jellien's mouth, and it starts choking on it, falling behind the couch.
The next morning, SpongeBob puts the Jellien into a cage as he leaves for work. It escapes, and consumes Gary as he sleeps, as well as the plant next to him. His tentacle spits out another small pile of goo, which reveals a Jellien Gary-plant hybrid. The scene switches to the Krusty Krab, which is completely filled with Jellien Bikini Bottomites, except for one man. Said Jellien Bikini Bottomites order Krabby Patties but "hold the mayonnaise" until the non-jellien orders a patty with extra mayonnaise. Jellien Mr. Krabs comes and says that they were "out of the condiment called mayo," and places a jellien on his's head. SpongeBob thinks that is weird, because the Krusty Krab had a fresh wall of mayo in the freezer. He then tells Jellien Patrick that he is getting mayo for the guy's patty. Patrick turns his head around, his torso still facing the grill, and yells "No mayonnaise!" Then his mouth tentacles consume the patty. SpongeBob goes to the freezer and grabs a box of mayo, then looks through the peephole. It shows everyone in town, minus Sandy, hibernating in transparent green cocoons hanging from the ceiling, as the Jellien King commanded his jelliens to do stuff for him. He saw it in a horror movie.
SpongeBob realizes that something is very wrong. He is then ordered by Jellien Mr. Krabs to take a nap. SpongeBob flees from the Krusty Krab, with several Jellien Bikini Bottomites chasing him. Afterwards, he is captured and kidnapped by Sandy. The latter tickles him, and he giggles, showing he is not a jellien clone. They figure out that the jellien's weakness is mayonnaise since they ordered food with no mayo. They then exit with sunglasses with a lens that look like jellien eyes. Unfortunately, when joking in front of Jellien Mr. Krabs, SpongeBob elbows Sandy, knocking off her sunglasses, and Jellien Krabs shouts "imposters!," which knocks off SpongeBob's sunglasses as well. The latter quickly grabs a mayo sprayer and destroys the entire town of Jellien clones. When a clone is destroyed, the real person of the clone awakens, and the cocoon they were trapped in disintegrates.
After dealing with the Jellien Patrick, who was the last one, SpongeBob and Sandy find the hideout, containing every Bikini Bottomite cowering in fear. SpongeBob destroys one side of the Jellien King's jelliens, but the mayo starts to freeze. He tosses the mayonnaise from the jar, but it freezes as well and lands in between the Jellien King's eye stems. Sandy turns up the heat, and the mayo melts, destroying the Jellien King. The remaining several jelliens, not hit by mayo, then pop like bubbles. SpongeBob explains everything, which takes eleven minutes. Patrick tastes the jelly and compliments it as a relish. Soon, the goo remaining from the clones and jelliens is served as Evil Clone Jelly Relish for $4 extra than regular Krabby Patties. Patrick then orders a Relish Patty 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 on an unsolved cliffhanger.
- The Jelliens saying "Hold the mayonnaise."
- The Jelliens hissing at people.
- SpongeBob screaming "random guy".
|( ‣ ) Associated production music|
|( • ) Original music|
|( ◦ ) SpongeBob music|
‣ Lost in the Galaxy [#36] - Harry Lubin [title card]
‣ Honolulu March - Hans Haider [opening at Jellyfish Fields]
‣ Wailing Theremin 2 - Harry Lubin ["Does Jellyfish Fields seem different today?"]
• Solo Steel and Vibes 1 - Jeremy Wakefield, Nicolas Carr ["All this failure sure is making me tired."]
‣ Desolate Lands - Harry Lubin [SpongeBob goes by the cave]
‣ Hostile Space - Harry Lubin [jellien leader sends minions out]
‣ Planet Xz-3 30 - Gregor F. Narholz [Patrick is cloned]
‣ Alien Abduction [#11] - Harry Bluestone, Emil Cadkin ["I too have caught many jellyfish."]
‣ Alien Abduction [#10] - Harry Bluestone, Emil Cadkin [Squidward is cloned.]
• Solo Steel 3 - Jeremy Wakefield [SpongeBob goes to bed]
‣ Desolate Lands - Harry Lubin ["I can't sleep."]
‣ Some Things To Know About Monsters - Eban Schletter [SpongeBob watching a horror movie]
• Solo Steel 1 - Jeremy Wakefield [the next morning]
‣ Lost in the Galaxy [#35] - Harry Lubin [Jellien clones Gary.]
‣ Out of the Crypt [#1] - Harry Lubin [Gary is cloned]
‣ Deep Shadows - Eban Schletter [line of jellien clones at Krusty Krab]
‣ Death of the Alien 1 [#38] - Harry Bluestone, Emil Cadkin [clones hiss at a customer]
‣ Dark and Scary - Harry Lubin [jellien Patrick cooking patties]
‣ Evil Alien Attack 1 [#14] - Harry Bluestone, Emil Cadkin [jellien leader in the freezer]
‣ Twilight Zone - Harry Bluestone, Emil Cadkin [jellien clones chase SpongeBob]
‣ Undercover - Harry Bluestone, Emil Cadkin [SpongeBob is dragged into Sandy's treedome]
• Hot Steel and Slide Licks (a) - Jeremy Wakefield [Sandy tickles SpongeBob]
‣ Lost in the Galaxy [#35] - Harry Lubin ["So you don't like mayo... just like a jellien!"]
‣ Shock Happening 1 - Harry Lubin ["We'll never get past... Them!"]
‣ Spongeburglar - Nicolas Carr [SpongeBob and Sandy in disguise]
‣ Desolate Lands - Harry Lubin ["Greetings, fellow clone."]
‣ Death of the Alien 1 [#39] - Harry Bluestone, Emil Cadkin ["Imposters!"]
‣ Evil Alien Attack 1 [#14] - Harry Bluestone, Emil Cadkin [jellien leader growls at everyone]
‣ Death and Destruction 1 - Harry Bluestone, Emil Cadkin [SpongeBob defeats the jellien leader]
• Great Idea Patrick - Nicolas Carr [Krabs gets an idea]
• Pirate's Opus - Michael Bolger, Nicolas Carr [Krabs serving relish patties]
‣ Lost in the Galaxy [#35] - Harry Lubin [SpongeBob thinks for a second]
‣ Out of the Crypt [#1] - Harry Lubin [The End?]
- The episode is available on the Complete Eighth Season, It Came from Goo Lagoon, The SpongeBob SquarePants Collection, The SpongeBob SquarePants 8 Season DVD Collection, Beware the Hooks, SpongeBob SquarePants Vol. 13, The Best 200 Episodes Ever, and Next 100 Episodes DVDs.
- SpongeBob calls Jellien Harold "Bill" Reginald "Random Guy." This is a reference to the fact that Harold is a background character on the show.
- This episode breaks the fourth wall when SpongeBob explains the whole story to everyone; the time card reads "Eleven Minutes Later," which is also the length of this episode.
- SpongeBob's spatula is cloned as a jellien even though it is not alive. However, in "All That Glitters," SpongeBob's spatula is indeed alive and in "The Curse of Bikini Bottom," when he snaps his spatula in half, it has a ghost.
- The Jelliens leave the mayo boxes to cover their activities even though that is their weakness.
- It is revealed in this episode that mayonnaise is another thing that can be added to a Krabby Patty, as the Jelliens order them without it and the normal customer wanted extra mayonnaise.
- Even still, the mayonnaise is still not shown to be put on a Krabby Patty in this episode.
- The title card background is similar to the planet that SpongeBob and Squidward are teleported to in "SquidBob TentaclePants."
- Because Gary is next to a plant when he got jellified, the clone is a hybrid of plant mixed with the latter.
- Squidward is not seen being cloned by the Jellien. Jellien Patrick just shoved it through his door and the goo is then spat out and morphed into Jellien Squidward.
- In the original airing, this episode aired first, while "Are You Happy Now?" aired second. In later airings, the episode order is reversed.
- This episode premiered on the same day as the 2012 Kids' Choice Awards.
- This is the seventh episode (along with the sister episode "Are You Happy Now?") to premiere on the same day as the Kids' Choice Awards. The first was "Help Wanted"/"Reef Blower"/"Tea at the Treedome" in 1999, the second was "Krabby Land"/"The Camping Episode" in 2004, the third was "Krusty Towers"/"Mrs. Puff, You're Fired" in 2006, the fourth was "Born to Be Wild"/"Best Frenemies" in 2007, the fifth was "Nautical Novice"/"Spongicus" in 2008, and the sixth was "Sentimental Sponge" in 2011.
- This episode "premiered" twice on March 31, 2012: 10:00 am for an initial airing and then at 7:30 pm, right before the 2012 KCAs.
- Even though SpongeBob and Sandy eliminate all of the Jelliens and save everyone at the Krusty Krab, the only character still never shown to be saved by the pair on-screen is Gary.
- This episode was paired up with "Snooze You Lose" for the Massive Monster Mayhem Marathon on Nicktoons.
- This is the second time the Krusty Krab thermostat is used. The first is in "Krabs à la Mode" and the next time is in "Eek, an Urchin!"
- It is unknown how the Jellien were able to eat SpongeBob's spatula, since it is an inanimate object.
- Gary is not seen in the freezer with the rest of the Bikini Bottomites hibernating in transparent green cocoons hanging from the ceiling.
- The Jellien Clones put the mayonnaise SpongeBob used in the freezer even though mayonnaise is their weakness. However, they are unaffected by frozen mayonnaise.
- When SpongeBob first walks into the Jellien-infested Krusty Krab and notices a line of customers, there are two Jellien Clones in front of the normal fish. After the first Jellien Clone finishes his order, the normal fish comes up next, actually skipping the second Jellien Clone. It may be possible that the second Jellien Clone is eating with the first Jellien Clone.
- The title is a reference to Planet of the Vampires and Planet of the Apes.
- This episode is a parody of the 1956 horror film Invasion of the Body Snatchers.
- When Jellien Squidward tries to give SpongeBob a Jellien, it also has eyelashes just like the one Jellien Mr. Krabs gives to the customer. However, after SpongeBob leaves and Jellien Squidward still has the Jellien, its eyelashes are gone.
- When Jellien Squidward points out that the normal fish wants mayonnaise on his Krabby Patty, the patty is still on the tray. When SpongeBob takes the Krabby Patty from Jellien Squidward to go and puts mayonnaise on it, the patty is suddenly on a small plate.
- When SpongeBob first walks out of the Krusty Krab and bumps into Jellien Harold, he has his Krusty Krab hat on. However, in the next shot, when SpongeBob runs from the group of Jellien Clones, his hat is missing. Finally, in the third shot, after SpongeBob comes from behind the rock, his hat is suddenly on again.
- Throughout the episode, Jellien Patrick's belly button keeps disappearing.
- Just before Gary is engulfed by a jellien, his shell inverts colors in between scenes.
- At the end of the episode, when SpongeBob walks out of the kitchen with a Krabby Patty, his pants are a different shade of brown than usual.
- In the Russian version, the title card mistakes Andrew Overtoom as an animation director instead of Tom Yasumi.