The Legend of Zelda: Majora's Mask/Dancing Spirit

Requirements

 * Kamaro's Mask (for the Rosa Sisters)

Rewards

 * Kamaro's Mask
 * Piece of Heart

Kamaro
On Day 1 after midnight, head into Northern Termina. You'll find a man dancing on a mushroom. Jump onto it and talk to him to learn that he has no one to teach this dance to. He died before he could show anyone his dance. Play the Song of Healing for him to heal his spirit. In return, he'll lend you his Dancing Spirit in the form of Kamaro's Mask.

Kamaro's Mask allows you to "Dance" by pressing the button.

Rosa Sisters
On Day 1 or 2 at 6:00 PM to 6:00 AM the Rosa Sisters will be practicing in West Clock Town. Use the Kamaro's Mask to dance in front of them. They will praise you and consider you their master. They have finally found the dance they are going to use for the Carnival of Time! The give you a Piece of Heart for their grattitude.