The moon jelly is a rare jellyfish that appears in the episode "Mooned!"
Description[]
It is a large, rare glowing white jellyfish that lives on the moon. It only appears outside of the moon once every 25 years.
Role in episode[]
The Jellyson Group discuss the myth of the moon jellyfish, which one of the members does not believe exists. SpongeBob tells them about how Kevin C. Cucumber caught a moon jelly and tries to get his help to catch one. They both try to catch the moon jellyfish in Jellyfish Fields, but it heads to Bikini Bottom instead.
They trap the moon jelly in an alley, but the moon starts to phase out. However, several Jellyson Group members appear and start mooning the moon jelly, creating moonlight. SpongeBob and Kevin manage to finally catch the moon jelly, but Kevin gets carried to the moon while riding it, and they play chess.