Coins (Mario is Missing!)
From the Super Mario Wiki
The Coins are a single item in the NES, SNES and PC releases of Mario is Missing!. They are the various coins that have been thrown into the Trevi Fountain in Rome. The Coins are stolen by some Koopa Troopas when they invade the city, therefore causing the fountain to be closed until they are returned. They are then taken by Luigi, who grabs them from a defeated Koopa Troopa and then shows them to various people within the city. All of them recognize the Coins as belonging to the Trevi Fountain. After gathering enough information, Luigi confirms the genuine nature of the Coins with the Trevi Fountain's information booth and returns them to their rightful place.