Season 2 - Episode: Jellyfish Hunter
SpongeBob is out jellyfishing and he finds this rare blue jellyfish. He tries to catch it but the jellyfish is too fast and sneaky and swims away. SpongeBob 's rebuttal: "Someday I'll catch old No Name". The transition cuts to SpongeBob eating at the Krusty Krab. He's on his lunch break. For lunch he pulls out a krabby patty and adds jellyfish jelly to the patty. A customer tastes some and ends up singing a song that ends up being one of Squidward's records. After singing the song, the customer says it's the best thing he's ever tasted, so he'll be coming back every day for the rest of his life. The camera cuts over to Mr. Krabs who looks relieved.
So Mr. Krabs tells SpongeBob to go jellyfishing, not knowing that Krabs has an elaborate scheme involving jellyfish. After several attempts, SpongeBob catches all the jellyfish in the fields, the population goes dramatically to zero. SpongeBob attempts to go home, not knowing that No Name is chasing him. He senses two tax men near him. He says "It feels like somebody wants to sell me something". One tax man tells the other "I told you he was onto us". SpongeBob then runs home and closes the blinds and shades. Then a series of strange events start to happen. No Name, acting like a human, uses a pair of wire cutters to cut the power to his house. SpongeBob nervously suggests that he forgot to pay the bill, then laughs. Then his phone rings with No Name breathing deeply and heavily on the other end. SpongeBob then goes into his kitchen and notices a krabby patty with blue jelly. He screams "Blue jelly???". No Name appears outside SpongeBob 's house. Then it shows SpongeBob inside an empty jar. No Name flies SpongeBob nearby him. No Name takes him to a nearby factory. A series of elaborate shots show that Mr. Krabs is behind the whole plot to destroy all the jellyfish and the fields. Especially getting the jelly out of them.
SpongeBob approaches Mr. Krabs saying "Stop this, stop this right now!". Krabs nervously says he's having a tea party.
No Name shocks SpongeBob reminding him what evil deed Krabs is up to. Eventually, a voice-activated door opens up, thus freeing the jellyfish. They all sting Mr. Krabs and fly home. Krabs says "I'm taking jelly off the menu".
SpongeBob realizes/discovers what No Name has done. Rather than attempting to catch him, he calls him a friend. Then No Name stings him and the episode fades to black.
The moral in this is that it's wrong to tease the environment.