Stone Tower Temple

The Stone Tower Temple is the fourth main dungeon in Majora's Mask.

Entrance to the Temple
The dungeon is at the top of Stone Tower. Link can access this temple after learning the Elegy of Emptiness, which invokes lifeless clones of Link so that slacked switches can be pressed and held; this is the only way to activate the platforms that allow the young hero to make his way to the top, where the the lifeless clones are needed again to get access to the entrance itself.

Themes and Navigation
Unlike the other three dungeons in this game, the Stone Tower Temple requires the use of all four of Link's forms: Hylian, Goron, Zora, and Deku. This dungeon is also unique in the fact that, thematically, it doesn't reflect the current situation of the region of Termina where it is located. Ikana Canyon is experiencing a dark age because of the rise of spectra, undead creatures and other beasts; in contrast, Stone Tower Temple does not even show the depressing atmosphere like the outside conditions. Instead, it's a light-themed dungeon that features a potpourri of other elements, including fire, water, and even sky; in addition, the setting of the boss battle is desert-themed.

Hylian Link is useful to solve puzzles related to light, as he's the only form with the Mirror Shield. Nearly midway through the dungeon, he will encounter the Garo Master, whose defeat will grant him the Light Arrows. These mystical arrows can do something that isn't seen in any other Zelda game to date - turn the dungeon, and the whole of Stone Tower, upside down. This is done by firing a Light Arrow into the Red Emblem fastened to the wall just outside of Stone Tower Temple. Other than that, the Light Arrows are also used to twist some rooms, as well as to defeat certain enemies whose weak points are evidently marked by emblems not unlike that of the temple's entrance.

As for the other forms, Goron Link is useful to cross lava rooms, and his brute force will also be called for use. Zora Link needs to swim through a large body of water, and while Deku Link is already required to fly through a chasm prior to the Garo Master's room, he becomes entirely vital when the temple is upside down, as most of the rooms will turn into large chasms due to the new position of the sky. The Boss Key is guarded by Gomess, who can only be defeated with Light Arrows and then the sword. A corridor containing a tougher than usual Eyegore is found on the way, and the young hero must defeat this Eyegore to continue. The creature's defeat reveals a chest containing the Giant's Mask. Once this is obtained, Link can continue until the boss room is reached. Inside the room, he will find himself in a desert, which is the home of the temple's boss, Twinmold. Defeating Twinmold yields a Heart Container and the final quest mask, Twinmold's Remains.

If Link collects all 15 Stray Fairies, he will be rewarded with the Great Fairy's Sword, the most powerful blade in the game.

Theories
Some theorists who study the design and symbology of the Temple, and Majora's Mask in general, conclude that the structure has connections to the Goddesses of Hyrule and the Majora's Mask itself. It has been suggested that the tower was intended to directly blaspheme Din, Nayru, Farore, and their Triforce with sexual connotations.

Trivia

 * This is the only area in the game where normal-sized Poes are found.
 * Close observation of the dungeon map reveals that once the red emblem is hit with a Light Arrow, the temple not only flips upside down, but mirrors itself as well.
 * Similarly to the way the temples could be completed out of the natural order in Ocarina of Time, the Stone Tower Temple can be completed before the Great Bay Temple as long as the player first obtains the hookshot from the Pirates' Fortress. Ice Arrows are not needed to reach the top of Ikana Canyon, as standing at a close enough edge is enough to grapple onto the small tree.
 * In the dark room with the Armos statues below the area that branched off to the halls containing a Death Armos squad, there are two Armos Statues that cannot be moved, yet getting near one makes the "Grab" command appear.
 * The Stone Tower Temple has many remarkable similarities to the Desert Palace dungeon from A Link to the Past. Both dungeons have strikingly similar architecture (structures like disembodied heads flanking one larger one for which the mouth serves as the entrance to the dungeon) and are located in desert environments. Moreover, the bosses of both dungeons, Twinmold and Lanmola, are nearly identical in terms of physical appearance, surroundings, mannerisms and weaknesses.