go to big boo's haunt and get on the second floor, you dont need the stairs, you can triple jump up if you dont already have them. then, you need to get on the right door next to you, not the far right one.then you need to go forward and there will be a ? box.either break it and get the power flowr and float up or jump on top of it.there will be a third floor but only a tiny piece of floor.get on there and go throgh the door and jump through the luigi painting.this should also help you get two other stars.once you have gone through the luigi painting, you have to go through the right door, then the left, then the right and then the left again i think.then go across the bridge and go up those platforms.jump through the hole and you will be in the king boo place.go towards the mirror and king boo will appear.look in the mirror and you will see king boo coming towards you.backflip and groundpound.then you cant see him in the mirror, you see him normally.do a groundpound and when he appears in the mirror, get close and do a groundpound.and you have beaten him.
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