Mystery Piece

The Mystery Piece is a key item that appears in Kingdom Hearts Re:coded. There are four pieces, which combine together to create Traverse Town's data Keyhole.

Kingdom Hearts Re:coded
Under Cid's request, Data-Sora searches for the triplets Huey, Dewey, and Louie, who had gone missing when the Bug Blox had started to corrupt Traverse Town. One by one, Data-Sora manages to find each triplet in the Second and Third Districts. Before each of them return to Cid, they all give a Mystery Piece to Data-Sora, which they had found during their explorations across Traverse Town. No one knew what the strange, shiny objects were, however, once Data-Sora had a piece from each triplet, he noticed that they fit together to form an incomplete Keyhole.

After all the triplets had returned to Cid, the black-coated figure encountered Data-Sora and spoke to him briefly before giving him a final Mystery Piece. With all four pieces joining together, a complete Keyhole was created. From the Disney Castle library in the real world, Mickey Mouse tells Data-Sora in the datascape that the Keyhole is probably the source of this world's bugs. Under this assumption, Data-Sora jumps inside and battles many bugs and Heartless within the Keyhole, eventually defeating the Guard Armor, clearing the town's bugs.