Molgera

Molgera (モルド・ゲイラ, Morudo Geira) is a gargantuan Lanmola-like creature that lives in the depths of the Wind Temple, waiting for its prey. It must be defeated in order for Makar to be placed in as the new sage of the Wind, and for the Master Sword to return to full power. 

Strategy
When Molgera emerges from the sand, Link must be careful not to get too close to its gaping mouth. It will devour him and cause severe damage before spitting him back out. Link must get close enough, however, and use L-Targeting to grab its tongue with his Hookshot. Now that it is near him, Link uses the Master Sword and slashes away. This is what causes damage to Molgera.

One of its other attacks is to send out three baby Molgeras to annoy Link. He uses the Hookshot to latch onto them, pull them to his side, and slash them. They will reward him with hearts when they die. In the meantime, Link must watch out for Molgera as it emerges from the sand and flies through the air, attempting to crush him when it dives back in. Link keeps hooking and slashing its tongue until it is done. It will fly into the air and explode in a shower of sand, revealing the Triforce crest with the blue light.

Link's rewards from this fight are a Heart Container and a fully powered Master Sword.

Trivia

 * Molgera is possibly the largest boss Link has ever fought, along with Dark Dragon, Morpheel, Eox, Stallord, Bongo Bongo and Twinmold.
 * Molgera's name is a play on Mogura, the Japanese word for mole.
 * This boss may be inspired by the Sandworms from Dune.
 * Molgera's tongue can be extended; simply Hookshot it, move back, and Hookshot it again. The tongue can stretch across the room. When it's overstretched, you can see that it actually consists of several unconnected spheres, although this is most likely just an glitch.
 * It is also possible to latch onto Molgera's tongue while it's in the air if you time it right. Molgera will be frozen in the air if that happens.
 * The song that plays during the fight with Molgera was put into Super Smash Bros. Brawl