Gummy is a giant ball of chewing gum that only appears in the episode "The Gift of Gum."
It is one of Patrick's greatest possessions. He gave it to SpongeBob on Best Friends Day. SpongeBob was disgusted by Gummy. It had a slice of moldy pizza, a pair of hideous underwear, a toothbrush, and all other sorts of nasty things stuck to it. Eight fish even lived in it (which Patrick seemed unaware of), but SpongeBob freed them. SpongeBob hated it so much, he tried to dispose of it in any way he could, which included burying it, and dumping it in a trash can. Later, SpongeBob, Sandy, and Squidward all were stuck in Gummy. When SpongeBob gave it back to Patrick, he ate it, but burped it, which entirely covered Bikini Bottom in gum.
There used to be a living pair of ripped underpants inside of Gummy that knew who Patrick was.
Originally, the writers planned to color the gum blue instead of pink.