Enter the door at the extreme right of the home area, then hustle by the pair of pouncing pincers and let the falling crate pancake Wario. Climb the platforms leading to the door Wario entered; near the top, jump off and drift left to the Silver Key. Enter the door at the top of the grassy home area and drop down to the plain below for a battle with Wormwould. Bash this spineless boss and it will retreat, then pound on its scowling head. Three pounds and it's history. You'll earn a Music Box here.