Costume Mushrooms allow Mario to look like various other amiibo characters. The sound effects and/or music may also be changed while Mario wears a costume. In gameplay terms they behave like normal mushrooms except that Mario's height is not increased while he wears the costume. Mario does not gain any special powers based on his costume. When Mario is hit, he loses the costume. Some costumes have different death effects, however because Mario normally loses the costume when hit, only things which kill Mario instantly (such as falling off the screen) will make these effects play.
When a player completes a 100 Mario Challenge or 10 Mario Challenge while wearing a costume, whoever is rescued (the Mushroom Retainer or Princess) will react differently.
|Costume||Mushroom Retainer's Quote||Princess Toadstool's Quote|
|None||"Mario! It's terrible! Princess Peach has been taken to another castle!"||"Thank you, Mario. You're my hero!"|
|Toad||"Ah, Captain! It's terrible! Princess Peach has been taken to another castle!"||"Thank you, Toad. I can always count on you."|
|Princess Peach||"Princess Peach?! How did you escape!... Oh, it's just a costume..."|
|Bowser||"B-Bowser?! Aaaaghhhh! I thought you'd taken the Princess to another castle!"||"Oh, my... Bowser?! Did you save me yourself? How very sweet of you!"|
|Other||"I'm sorry to disappoint you, but the princess has been taken to another castle!"|
Most Costume Mushrooms can be unlocked by placing a character amiibo on the scanner while in the editor, or by completing the 100 Mario Challenge, which unlocks a single new costume each time. However, you can only unlock approximately 20 costumes for completing the Easy challenge, and 45 for completing Normal. These limits seem to vary, however--numbers as low as 15 and 40, respectively, have been reported--and the reason for this variation is unclear.
Several Costume Mushrooms are unlocked only by completing specific Event Courses. Additionally, the Builder Mario costume can be unlocked only by completing all three levels of Gnat Attack, and the Fighter Fly costume can be unlocked only be completing all three levels of the hard version of Gnat Attack.
Check http://amiibo.wikia.com/wiki/Super_Mario_Maker for unlockables.