Moldarach

Moldarach, Thousand-Year Arachnid (千年甲殻蟲モルドガット), is the boss of the Lanayru Mining Facility, the third dungeon from The Legend of Zelda: Skyward Sword. It is a large scorpion. An identical arachnid can be found as a mini-boss in the Shipyard. Apparently, Moldarach is an Aracha that has survived its 1,000 year life.

Battle
In order to damage Moldarach, Link must swing his sword either horizontally or vertically, depending on the orientation of Moldarach's pincers. Moldarach attacks Link by grabbing him with its pincers, then by striking him with its stinger. Once a claw has sustained enough damage, it will fall off.

When both claws have been rendered useless, Moldarach's prime weakness will instead be its head. It will now change its attack strategy to jabbing with its stinger or ramming with its head. When charging the jab attack, its eye will turn red, signifying the weakness. If it does manage to successfully charge, a side-jump or backflip is enough to successfully dodge. When it burrows under the sand, it will attempt to get under Link, and if successful it will jump up from under him, damaging him, and immediately transition into a charge. Link must use the Gust Bellows to reveal it before it jumps up and charges.

When it is defeated, the sand in the room drains, revealing an unused turntable for mine carts, as well as a route leading to the Temple of Time.

Etymology
The name Moldarach is likely a portmanteau of "mold", loose soil, and "arach", a shortened version of "arachnid", since it is a scorpion. The "Mold" in it's name may be a reference to Moldorms, due to it's digging abilities.