The Jellion King is an evil alien jellyfish who has the power to clone anything and make it a living thing. He appeared in Planet of the Jellyfish. He cloned the Jellyfish and the entire population of Bikini Bottom. He kept the non clones in a ice shaped cocoon where had operated in the freezer of the Krusty Krab. He was defeated when the last drop of mayonnaise from the bottle in the freezer in the Krusty Krab when the heat was turned on. When he died he melted into green slime which later became a a menu option for the Krusty Krab. It was called Evil Clone Jelly Relish for $4 extra than regular Krabby Patties served with the patties.
He is a giant alien with tentacles and his skin is light green.