Kamaro's Mask

Kamaro's Mask is given to Link by the spirit of the dancer Kamaro in Majora's Mask.

Location
Near the Snowhead area of Termina Field, where the giant mushroom-like objects are located, between midnight and 4 AM on the First or Second Day, some music can be heard. Link must jump on top of the mushroom-like object that is the source of the music to find the spirit of Kamaro, a dancer. Kamaro is afraid that his dance moves will never be passed down to the new generation, and asks that Link rest his soul. By playing the Song of Healing, his musical talent will be encased inside a mask. He entrusts the young hero with his final request, to spread his dance across the world.

Uses
The mask has an unusual property: when worn, it allows the wearer to perform Kamaro's dance.

When in West Clock Town at night, Link can find the Rosa Sisters trying to come up with a dance for the Carnival of Time. If Link stands in front of them and performs the dance, they will learn it and thank him, calling Link "master" and giving him a Piece of Heart.

Trivia

 * Interestingly, both the music heard near the Rosa sisters and near Kamaro are the one and same, even though the dances are different.
 * It's unknown how an user can wear the mask without being able to see, as his or her face would be covered by the lower part of the mask.