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When Luigi first encounters Boos in the Storage Room, he returns to Professor E. Gadd's lab. E. Gadd upgrades his Game Boy Horror, so that it has a device that scans where the Boos are found in each room. Luigi finds 50 Boos (51 Boos including King Boo) throughout the mansion (15 make up Boolossus). Each Boo is a parody name, one of them notably is Game Boo Advance, obviously a parody name of the Game Boy Advance.