Seashell

Seashells are special items that are present in several Zelda Games.

In Link's Awakening:

Mysterious Seashells are special items that the player can gather. If 20 seashells are taken to the Seashell Mansion, the player's sword is upgraded to Level 2. The new sword has an increased attack power and the ability to shoot beams.

In Minish Cap:

In this game, Seashells are used to unlock figurines in Gustov's shop. Once all the figurines have been unlocked; the player may then speak to a special NPC sitting near the building to the left of the item shop in order to unlock the sound test and a piece of heart.