The rock balloon is a balloon that appears in the episode "Krusty Katering."
It is made out of multiple balloons and is purple, violet red, light green, red, and yellow. It is lumpy and anyone who holds it will automatically fly away.
When a kid at the birthday party wants a balloon, Patrick has to think fast. Then, he makes a rock balloon. He then gives the rock balloon to the kid and then the kid flies away with it for the rest of the episode.