There's an actual glitch that lets you play as master hand using the controller but only if it's plugged into player 3's slot. And MH actually has moves mapped out on the controller.
How is that even a thing?
>>384197127
It means that the game is coded in a certain way, something similar to this:
http://hopooo.tumblr.com/post/160808393488/devblog-3-character-body-system-hi-this-is