Bowser hires Motley Bossblob to take over the Mushroom Kingdom while Rosalina has come for vacation. Mario, Peach and Rosalina try to defeat Motley.
After failing, Motley sends them all to the Underground. He then asks Bowser to pay him, and Bowser refuses, so Motley sends Bowser to the Underground with Mario, Peach and Rosalina. They need to find a way out and defeat Motley before the Mushroom Kingdom is ruined!
Switch Mario can switch bodies with an enemy, and no enemies will attack you, but the enemy in Mario's body will try to defeat him. He can also switch with Snake Blocks, in which case you don't have control of the Snake Blocks, but your body will follow you. You turn back to Super Mario after being hit by an enemy or at the end of a Snake Path.
As Statue Mario, Mario has the powers of Tanooki Mario, but he can turn into a statue instead of doing a ground pound, making him invincible, but unmovable. After being hit while not in Statue form, he will turn back into Super Mario.
When Mario hits one of these from below, he will wear the ♪ Box on his head, making all enemies begin to dance in place until he is no longer wearing the ♪ Box. When jumping on them, they will eventually send him to Coin Heaven.