This is someone else's topic, but I DON'T CARE.
First, you know those boos that trun into gray squares when you look at them in the Choco Ghost House? Well, position them so that they turn into blocks near the area up to the door. then climb them up! Or you can take the cheater way and use a cape.
(Note: that was for SMW, not SMA2. They may have changed it.)
As for Waluigi in SMK: SC, that is a lie. Your were grossly misinformed. There are NO hidden characters in the game.
You know what? I got really, really bored one day so I decided to change my signature.