Paper Mario: Sticker Star is an RPG created by Nintendo and Intelligent Systems. It was released in 2012 and is the fourth installment in the Paper Mario series. On the night of the Sticker Fest in Mushroom Kingdom, the wish-granting Sticker Comet arrives. Bowser comes for the comet, resulting in it breaking apart and scattering the Royal Stickers. One Royal Sticker lands on Bowser, who becomes so powerful that even Mario can't stop him. With help from Kersti the sticker fairy, Mario sets out to collect all the Royal Stickers and save Princess Peach, whom Bowser has once again kidnapped.
At the beginning of Rumble Volcano, Kersti is eaten by Petey Pirahna, who is described as gluttonous in this game. His bloated belly isn't seen until the boss battle with him starts. After Petey does his spin attack, Mario can knock him over and attack his navel, making him spit out everything he has eaten (Jump stickers, Dry Bones, and finally Kersti).