The Music Box is a common item found in Super Mario Bros. 3. It makes all Hammer Bros. on the map screen, as well as the Munchers in World 7, fall asleep so that Mario and Luigi can sneak past them. After a while, they will wake up again. The song that's played is a soothing version of the Super Mario Bros. main theme song. The pitch level of the music was adjusted for the SNES remake in Super Mario All-Stars.
Music Boxes also have a large role in Wario Land 3; they are so involved that the game is even known as Wario Land 3: The Mysterious Music Box in Japan. In fact, this game is set within an enigmatic Music Box with a world inside of it, and focuses on the collection of five different Music Boxes, which, if all played, could free a hidden figure who, claiming to be the Music Box World's unjustly accursed leader, helps Wario through his quest. Wario, in the end, collects the five Music Boxes scattered around the larger one and frees the figure, only to discover that he is the evil Rudy the Clown; Wario then defeats Rudy and saves the Music Box, which he is permitted to leave. Wario later claims the Music Box World as his own, as evidenced by its cameo in his house in WarioWare: Twisted!.
In the book Koopa Capers from the Nintendo Adventure Books series, Luigi tries to whistle the tune from the music box to escape the Sledge Bros. While it does make them drowsy, perhaps the fact that he was only whistling it keeps them from falling asleep completely.
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