Don Gero's Mask

Don Gero's Mask is a frog-shaped mask found in Majora's Mask, bearing the image of Don Gero, the conductor of the frog choir.

Location
To acquire the mask, Link must light all the torches lining the wall of the Goron Shrine using a Deku Stick before defeating Goht (the Bunny Hood makes this task significantly easier, but is not necessarily required); alternatively, Link can light them at once by shooting a Fire Arrow to the torch at the center of the chandelier of hanging pots on the ceiling. Doing either action will make said chandelier to spin. Link must then use the Goron Mask to roll off of the ramp on the top floor to collide with the pots until some Rock Sirloin falls to the floor. He must bring this to the Mountain Village (therefore having to avoid any enemy encounter) and give it to the Goron standing on a ledge who is hungry. He will thank Link with the Don Gero's Mask.

Uses
The mask allows Link to communicate with frogs around Termina to let them know that the Frog Choir is reuniting to sing again. Although Link can speak to them at any time, the reunion can only take place after Link defeats Goht and spring returns to Snowhead. Getting all five frogs to the choir will earn Link a Piece of Heart.

Trivia

 * On the third row of the Mask Subscreen, the Keaton Mask (Fox), the Bremen Mask (Falco), the Bunny Hood (Peppy), Don Gero's Mask (Slippy), and the Mask of Scents (Pigma) are said to represent Starfox characters, implying that Nintendo created the appearance of these masks (save for the Keaton Mask and Bunny Hood, both of which appeared in Ocarina of Time) with the sole purpose of hiding an easter egg in the game itself.