Grotto Key

The Grotto Key is a key found in Pirate's Grotto in Paper Mario: The Thousand-Year Door. It sits on top of a set of barrels by the left storeroom in the north area of the 2nd floor. To obtain it, Mario must use Koops or Admiral Bobbery to activate a switch near the wooden lift in the storeroom. The Grotto Key unlocks a door on the right side of the large stairway room.