SpongeBob is out jellyfishing in Jellyfish Fields. He catches a jellyfish, gently tickles out some of its jelly, and lets it go, naming it "Twelvy" on its way. He then spies a very rare blue jellyfish, the only jellyfish in the field he has never been able to catch and name, thus calling him "No Name." SpongeBob's attempt to catch this specimen ends in failure once again, despite having used himself as a rocket to get closer to it.
Later, SpongeBob goes on his five-minute lunch break at the Krusty Krab, and puts the fresh jellyfish jelly on a Krabby Patty. A customer notices it and asks him what it is. Believing that he is talking about the holes on his body, SpongeBob starts explaining them, but the customer quickly corrects him. After he explains the patty with jellyfish jelly, the customer is eager to try the jelly-covered patty, so SpongeBob provides him with a dollop. Amazed with its taste, the customer sings a song proclaiming its greatness and plops jelly on the patties of all the other customers, who enjoy it as well. Mr. Krabs comes out from his office asking who is playing Squidward's records, and SpongeBob explains how he was sharing his jelly with the customers and asks him to try it. Mr. Krabs at first reviles the thought of altering the patty's recipe, seeing it as mutating. He soon sees the potential profit after the first customer tells him that he will come back for lunch there everyday for the rest of his life (causing Mr. Krabs to hallucinate and see him as a dollar bill), and officially puts the new Jelly Patty on the menu.
SpongeBob is tasked to go out and gather as many jellyfish as he can. He is delighted to be paid for jellyfishing, but Mr. Krabs tells him that it is part of his free time. SpongeBob stills agrees, though he asks Mr. Krabs to keep the jellyfish comfortable while milking them for jelly. Mr. Krabs secretly states to himself that he will keep them comfortable "in his wallet," hinting that he does not care for their safety. SpongeBob catches several jellyfish, with Mr. Krabs demanding more every time, until Jellyfish Fields is completely deserted. SpongeBob concludes that there are no more jellyfish to catch, and begins to walk home.
As SpongeBob walks home he feels that he is being followed. He turns around mentioning that he feels like someone is trying to sell him something (much to the dismay of two salesmen following him). The thing following him is revealed to be No Name, but he hides every time SpongeBob looks back. SpongeBob states that he is not interested in anything his hypothetical salesman is selling and rushes home. Upon arriving home, he closes the blinds of his windows in panic but soon laughs off the incident. SpongeBob then gets a strange call from No Name that only features him breathing (making his identity unknown to SpongeBob) before the call abruptly ends, with the line seemingly having been cut. Nervous, SpongeBob laughs it off as a wrong number call, but the lights go off shortly after and he laughs that off as well by stating that Gary must have forgotten to pay the electric bill. SpongeBob later sees a shadow that he believes is Gary crawling into the house and later into the kitchen, which SpongeBob thinks is a good idea as Gary would probably find food there. Shortly after, he enters the dark kitchen and sees a Jelly Patty where the moonlight is shining in from the window. He eats it at first, but shortly realizes that something is extremely wrong when he finds that the patty contains blue jelly. No Name shows up and SpongeBob ends up captured in a jar himself by the blue jellyfish. It then takes SpongeBob to a secret factory farm, where he discovers that Mr. Krabs is forcefully wringing every jellyfish dry to increase his bottom line, draining, harming, and possibly killing them. Realizing Mr. Krabs' unscrupulous plan, SpongeBob angrily confronts him. Mr. Krabs claims that they are having a tea party which initially distracts SpongeBob, but No Name informs him of the trick and SpongeBob declares his intention to free the jellyfish. Mr. Krabs is shocked when SpongeBob suddenly picks up a pipe wrench, but he uses it to fix the squeaky bolts on the door, much to his relief. SpongeBob tries to set the jellyfish free but is unable to open the door to their cage.
Mr. Krabs laughs and boasts of his sturdy voice-activated door that only opens when he says "Open," which ends up opening the door. The freed jellyfish swarm over Mr. Krabs, who tries in vain to ride off on the bike used to power the machine before realizing it is only an exercise bike. The jellyfish then give him a mighty zap before flying off. Thoroughly charred, Mr. Krabs meekly decides to take jelly off the menu. SpongeBob vows to never again let his net be used for anything except pure sports, stating that jellyfish are not meant to be kept in captivity forever. No Name gently enters his net, allowing itself to be caught. Touched, SpongeBob decides to name the jellyfish "Friend," and they share a handshake that ends up shocking SpongeBob, who laughs it off as his hand proceeds to swell.
In the Fisher Price Interact TV version of this episode, the scenes where No Name makes the power in SpongeBob's house go out and when SpongeBob says goodbye to Twelvy are cut.
This episode was featured in the SpongeBob Earth Day Marathon that leaded up to the premiere of "SpongeBob's Last Stand" and the story in that episode is similar to this episode.
The French Narrator mentions the episode title when he says "Ahh, another beautiful day in Bikini Bottom's own Jellyfish Fields. An untamed world of natural order where the little jellyfish jellies roam free across the salty seascape. And where there is jellyfish, there is the Jellyfish Hunter."
The scene where Mr. Krabs says "More!" and looks very morbid has become a famous internet meme. This meme is known as "Moar Krabs."
In the UK, the shot where No Name cuts the power to SpongeBob's house is replaced with a shot on the door outside of SpongeBob's house at night.
This is the first episode to show Mr. Krabs as the main antagonist.
When Mr. Krabs is riding the bicycle, he wears his headphones on the sides of his eyes which may hint that his eyes and ears may be connected.
This is the sixth episode to feature the Krusty Krab without Squidward, although he is mentioned.
There is an innuendo in the scene where SpongeBob picks up the pipe wrench to fix the door; he seemingly has the intent to kill Mr. Krabs with it before his actual purpose for picking it up is revealed.
SpongeBob picking up the phone and hearing heavy breathing is a reference to the 1979 movie When a Stranger Calls.
When No Name/Friend sneaks into SpongeBob's house, he looks like a blob crawling around the floor. When he does this, he resembles ChuChu, a character from the video game Kirby's Dream Land 3.
When SpongeBob takes off and rockets are activated where his legs are, his pants drop off. This is referenced to booster stages in rockets built by NASA.
The way the jellyfish are treated in the factory is a reference to factory farming, particularly with the poor ethical treatment to animals.
When SpongeBob is only wearing underwear in Jellyfish Fields, his sleeves are still shown.
After Fred finishes his song, the crowd can be heard cheering for him, however, none of the fish are moving at all and only the cheering sound is heard.
When SpongeBob is being followed by the blue jellyfish, he says, "It feels like somebody... wants to sell me something!" However, the closed-captions read "tell" instead of "sell."
When Mr. Krabs says "The door will only open if I say open." It only opens the second time he says the word.
It could possibly be that it only activates when the word "open" is said clearly and loudly, as Mr. Krabs said "open" in a more defined way the second time, and if the door is voice activated, then Mr. Krabs' voice would have needed to be recorded, and he would have recorded it in a clear way. Additionally, there may have been a delay.
During the part where Mr. Krabs says "You'll never catch me!," his walkman can be seen in his pocket; then, after the scene zoomed out, his walkman in his pocket is gone.
The closed-captions misspell "Krabby Patty" as "crabby patty."
In the German version, SpongeBob says "Let me out!" in English untranslated.