How do you become luigi in Mario 64 ds?

Answer 1

To unlock luigi be Mario and go to the basement of the castle. This can be accessed by going through the door beside the level Cool Cool Mountain. A ghost will appear and follow him down the hall and out into the garden. It should be full of ghosts. There is one big ghost. Kill him and a little cage will appear. Jump into it to access big boos haunt. Now you should be outside a big house. Go inside and in one of the rooms there should be a red ! box. Hit it to reveal a power flower. Mario can float once he has one of these so float up to the balcony above you and through the door. There will be a luigi painting so jump into it. Get through there and after beating the boss you get a luigi key so you can now be luigi.