Patrick's underwear is a character who only appears in the episode "The Gift of Gum."
Patrick's underwear is an old pair of underwear that is white and light blue in color. It also has pink gum on it from Gummy.
Role in episode
Patrick's underwear is seen after it crawls out from Gummy. It crawls onto SpongeBob's face and tells him in a raspy voice, "You're not Patrick." SpongeBob screams in terror when he hears this and Patrick's underwear crawls away.