The Hungry Mouseketeer aka BlueShelledKoopaTroopa
I just now noticed that Luigi's Mansion (E ranked version) can be seen in the background of Luigi Circuit in Double Dash and the DS version of that track.
Given how infrequently these games sprinkle references like that, I wouldn't blame you for thinking a backdrop from the Mario & Luigi Superstar Saga remake is fan art. :Pyou know the drill! this mario house pic is fanart so please source it!!!