From the game The Legend of Zelda: Majora's Mask for the Nintendo 64.

Put on the bunny hood and head to Sakon's hideout. On the third night, roll at the crack at the right until you slip in. If you fall off the ledge inside, you will be put at the entrance of Ikana Canyon. Once you are in, make sure you are wearing the bunny hood. When you gain control of Kafei, bring up the mask screen and equip the Fierce Deity's mask in the spot where you have the bunny hood. when you gain control of Link, he will put on the mask and transform. Once you finish and Kafei has retrieved the Sun's mask, you will be outside of the hideout. Turn around, dive into the water and take the tunnel to the right. You will now be able to explore as the Fierce Deity! (hint: play the inverted song of time to be able to be the Fierce Deity longer.) Unfortunately, I have no idea how to change out of Fierce Deity mode without restarting or dying. And, you can not use any of your items.

Submitted by: lazio62