The Dragon Jellyfish is a gigantic jellyfish with purple spikes on his head, long tentacles, the same jellyfish looks with red polka dots, and he has a dragon tail. This creature was in a mind control spell by Planktonamor. He attacked the village and kindnapped Princess Pearl. SpongBob, Squidly, and Patrick were all sent to rescue Krab's daughter.
After the Dark Knight battle was over, the Dragon Jellyfish returns back to the wizard's palace and the letter shows to Krabs that he has to give him his kingdom or Pearl will suffer in boiling lava. The Dragon Jellyfish sees a Krabby Patty and takes it, then falls in love once he has eaten it. SpongeBob and Patrick have won and Planktonamor was zapped to death by the Dragon Jellyfish. He was seen again where King Krabs was making Krabby Patties and Dragon Jellyfish eats another patty.
- The Dragon Jellyfish hasn't been seen since "Dunces and Dragons", as SpongeBob will probably never go to medieval times again.
- The closest jellyfish in relative size to the Jellyfish Dragon was the King Jellyfish.
- Just like his possible descendant, King Jellyfish, Dragon Jellyfish seems to be easily calmed down when given food, as he stopped his rampage after being given a Krabby Patty by SpongeBob, and the King Jellyfish stopped his rampage after SpongeBob gave his a bubble resembling a delicious pie.
- It is possible that Dragon Jellyfish is who King Jellyfish gets the trait from.