After Grim's robe comes out of the washing machine, Billy and Mandy find Thromnambular, a talking skull with ruby eyes and a number nine imprinted on his forehead. Then, Grim tells them that the skull is a magical artifact imprisoned on Earth that must grant his nine wishes in order to be free. When Mandy asks Grim why he hasn't used any of the wishes, Grim tells her that the skull will corrupt the wishes and end up affecting the wisher. Despite this, Billy runs away with the skull and makes the first wish: (1) he wishes to be in an adventure (which parodies Indiana Jones and Jonny Quest), this backfires because Irwin is eaten, which Billy complains about getting him in trouble. After this, Thromnambular is found by different people who each make a wish: (2) Billy's dad wishes he could live again his High School years, but this backfires because he is not popular; (3) General Skarr wishes to rule on high, but this backfires because he asphyxiates in space; (4) Irwin (despite being eaten already in an earlier episode) wishes he was in a Hip-hop video, but backfires because he gets punched by Mandy; (5) Pud'n wishes he had a bunny, but he is attacked by it, because "Sometimes Love Hurts"; (6) Nergal Junior wastes his wish by wishing to know what to wish for; (7) Sperg wishes for a way to get into the girls restroom, in order to bully a girl into giving him a large sack of money, this backfires because he is turned into girl, and then insulted by the other girls for being ugly; (8) Mindy wishes to be a "big star", but this backfires when she is sent into space strapped to a rocket; (9) finally, Mandy tries to auction the last wish, but Grim gets ahead and wishes the kids never found the skull in the first place. This then goes back to the beginning of the episode where Billy is staring at the washing machine, followed by Mandy pushing him into it.
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