Bubble Buddy is a sentient soap bubble created by SpongeBob when he felt alone in the episode "Bubble Buddy." SpongeBob takes him to the Krusty Krab and Goo Lagoon, where the seemingly inanimate bubble inadvertently causes trouble and angers everyone it came in contact with.
At the Krusty Krab, he forces Squidward to remake his Krabby Patty several times in order to suit his alleged and outrageous preferences. According to SpongeBob, Bubble Buddy is lactose intolerant, no cheese, drinks shampoo instead of soda, prefers no crust, ketchup under the patty, pickles to the left, four squirts of ketchup, wheat buns, non-deli lettuce, and farm raised tomatoes; carnival style - and at some point before eating requires a massage. He also fails to pay for the meal, paying in "Bubble money", which is not real and quickly pops out of existence. Later on, at Goo Lagoon, SpongeBob and Bubble Buddy continue to make trouble. SpongeBob leaves Bubble Buddy with Scooter, who is buried up to his head in the sand, saying he will unbury him, and Scooter drowns when the high tide comes. When Bubble Buddy "has to go to the bathroom", SpongeBob leaves him in the bathroom for two hours, making everyone else wait. While dancing with Bubble Buddy, SpongeBob inadvertently insults the other dancing beach-goers by saying "shake that bubble butt," which the people take as calling them fat. When Bubble Buddy shakes Pearl's hand, which had just been dirtied by Grubby Grouper, making her never wanting to wash it again, it is cleaned off. After all these shenanigans, an angry mob is formed, who surround SpongeBob and Bubble Buddy. Just as he is about to be popped by a needle, Bubble Buddy suddenly comes alive, much to the shock of the people (except SpongeBob), and decides to leave, saying that "things are getting a little weird around here." A bubble taxi picks him up and he leaves with a suitcase and disappears into the sky. He then says, "Happy Leif Erickson Day!", to SpongeBob. Nobody seemed to mind that Bubble Buddy left as they agreed that this is still okay for them.
Bubble Buddy reappears in the episode "Bubble Buddy Returns." He sends SpongeBob a duty to babysit his rather troublemaking son, Shiny Bubble. Bubble Buddy makes only a minor appearance in this episode, appearing only in a flashback writing a letter to SpongeBob and in the ending when he picks up his son and thanks SpongeBob before leaving in his bubble plane. This episode also reveals the address of Bubble Buddy.
He makes two cameos in the Bikini Bottom Mall. He is first seen on the top floor when Pearl is eating a Hot Dog on a String, and is seen again near the Halian stand when Nocturna asks if Pearl got a job.
He appears in the video game Battle for Bikini Bottom as one of the major secondary characters who appear in several of the game's levels. He serves as a tutorial character who explains and teaches SpongeBob's various bubble moves.