The Mystery Mushroom is a new power-up debuted during Nintendo's Electronic Entertainment 2015 Conference. It can turn Mario into any character from the Mario universe and other franchises.
How it can be compatibleEdit
When tapping in an amiibo (Yoshi, Wii Fit Trainer, Link, etc.) on the Wii U Game Pad, it allows the player to put a character that slides to the middle of the Game Pad screen in a ? Block. Also, in the toolbar on the top of the Maker where you select items, there will be a ? Mushroom after you tap an amiibo, or do the following. You can also get new costumes from the ? Mushroom by completing the 100 Mario Challenge, and after you complete it you will get a random costume that either is not currently an amiibo or is currently one.
Note: You can only get the 30th Anniversary Mario costume via amiibo, and costumes can only be used in the original Super Mario Bros. theme. In the Mario 3 theme, the mushroom turns into a Super Leaf. In the Mario World theme it turns into a Cape, and in the Mario Bros. U theme it is a helicopter suit.