"Roll paper that is used for an auto-play piano. If you set it, the music on the paper will be played..."
— Item examination

The Piano Roll can be placed within the special grand piano in the Rockfort Palace games room. This will cause the piano to play the tune on the Roll. When playing, it will reveal the King Ant Object in a nearby-activated Slot Machine. It can be found after completing the Rusted Sword puzzle.