Molgera

This gargantuan Lanmola-like creature lives in the depths of the Wind Temple, waiting for its prey. This monster is directly responsible for the death of the Wind Sage. 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, be careful not to get too close to its gaping mouth. It will devour you and cause severe damage before spitting you back out. Get close enough, however, and use L-Target to grab its tongue with your Hookshot. Now that it is near you, use the Master Sword and slash away. This is what causes damage to Molgera.

One of its other attacks is to send out three baby Molgeras to annoy you. Use the Hookshot to latch onto them, pull them to your side, and slash them. They will reward you with hearts when they die. In the meantime, watch out for Molgera as it emerges from the sand and flies through the air, attempting to crush you when it dives back in. Keep 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.

Your 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 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.
 * 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.