SpongeBob is out jellyfishing. He catches a jellyfish, gets some of its special jelly, and lets it go. He names it "Twelvy," due to it being his twelfth catch of the day.
He then sees a very rare blue jellyfish which he calls "No Name," who is apparently the only jellyfish in the fields who was never caught, and compulsively tries to get him but to no avail.
Later, SpongeBob goes on his lunch break at the Krusty Krab, and puts the jelly on a Krabby Patty. After Fred asks about the patty and tries it, he sings a song proclaiming its greatness and puts jelly on the patties of all the other customers, who enjoy it as well. Mr. Krabs sees the profitability, and puts the new patty on the menu.
SpongeBob, to his great delight, is tasked to go out and gather as many jellyfish as he can, though he asks Mr. Krabs to keep the jellyfish comfortable. He continues to catch jellyfish, and Mr. Krabs continues to demand more, until Jellyfish Fields is completely deserted. SpongeBob concludes that there are "no more" jellyfish to catch, and begins to walk home.
After several close encounters and strange events, No Name captures him in a jar much in the way that SpongeBob catches jellyfish. No Name then takes SpongeBob to a secret factory farm, where he discovers that Mr. Krabs is cruelly treating the jellyfish (and possibly killing them) to increase profit.
Realizing that Mr. Krabs tricked him into catching all the jellyfish and lied about keeping them comfortable, SpongeBob then understands why No Name brought him here in the first place. He angrily confronts Mr. Krabs for his actions and decides to free the jellyfish to no avail.
Eventually, Mr. Krabs accidentally opens the voice activated door by saying the codeword: "open," freeing all the jellyfish, who then all zap Krabs at once in a great explosion. They all fly free, and he is forced to take Jelly off the menu. Spongebob names No Name as "Friend", and gets his hand zapped in a handshake.
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.
In the Fisher Price Interact TV version of this episode, the scenes when No Name makes the power in SpongeBob's house go out and when SpongeBob says goodbye to Twelvy were 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 scene where Mr. Krabs said "More!" and looked very morbid has become an internet meme. This meme is known as "Moar Krabs."
This is the first episode to show Mr. Krabs as the main antagonist of an episode.
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.
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."
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 .
SpongeBob takes out the wrench and loosens a bolt on the door, but after Mr. Krabs sighs in relief, the bolt is gone.
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.
After Fred finishes his song, you can hear the crowd cheer 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 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. Krab's voice would have needed to be recorded, and he would have recorded it in a clear way.
The closed-captions misspell "Krabby Patty" as "crabby patty."
When SpongeBob is only wearing underwear in Jellyfish Fields, his sleeves are still shown.