The Jellyfish is an enemy that appears in Pac-Man World 2 in the ocean levels. They only float around without targeting Pac-Man, or having any unique interaction with him. If Pac-Man touches one, it stings him and makes him lose one health-wedge. The Jellyfish cannot be defeated, and must be avoided.
In Game Descreption
"The Jellyfish simply floats in the water, but beware of its stinging tentacles."