Prince Mush
Prince Mush used to be the Champion of the Glitzpit, but he disappeared mysteriously. When Mario enters the Glitzpit, he learns strange things about it from a mysterious stranger called X (who contacts him with his Mailbox SP), and Bandy Andy.
When Bandy Andy and King K. go missing, X helps Mario find a secret storage room. King K. and Bandy Andy are both there, unconscious.
When Mario breaks into Grubba's room, he finds a ntoe. Grubba was using the Gold Star to suck energy out of Prince Mush, King K. and Bandy Andy! When Grubba comes in and sees Mario, they battle in the arena. After Mario wins, Jolene, one of the Glitzpit staff, reveals that she was Prince Mush's sister, and she helped Mario to solve the mystery by sending e-mails.
Jolene thinks Prince Mush is gone, but suddenly he comes out of the machine and they are reunited. They give Mario the Crystal Star.