Twinmold

Giant Masked Insect: Twinmold (大型仮面虫ツインモルド, Giant Masked Insect: Tsuinmorudo) is a pair of gargantuan insects found in the fourth dungeon (Stone Tower Temple) in Majora's Mask. This monster is responsible for all the curses that have been placed on Ikana Canyon, and it is keeping the fourth giant from its freedom. Twinmold's name is obviously a reference to Moldorm but with the '-orm' removed and "Twin" placed in front, with 'Twin' referring to the fact that there are two of them.

Strategy
Twinmold is defeated by Link, who must hit their heads and tails. This can be done as normal Link by Z-Targeting it and using arrows, bombs, or the sword to attack. Alternately, Twinmold can also be defeated by using the recently acquired Giant's Mask, and the sword to even out the size difference. Link's chances of scoring a hit improve tremendously while wearing the Giant's mask (the only flaw is that Z-Targeting is disabled). Using the Giant's Mask also greatly drains the young hero's magical energy. If he plans on wearing the Giant's Mask, it's wise to have a lot of potions stored in the Bottles (and the more of them are earned up until that moment, the better); another plan is to drink a bottle of Chateau Romani before the battle, which will suspend the consumption of Link's Magic Meter and make it last forever. If it's not chosen to use Chateau Romani or any other potion, it's possible to find magic jars after destroying the pillars found throughout the stage. In the event Link is out of magic and there is no way of restoring it, arrows can be used then. Fierce Deity's magic attacks are also an option, preferably with infinite magic power, as this approach can take some time, since the accuracy of the attacks can be unsatisfying. After defeating Twinmold, their bodies explode and their heads crash into the sand. The young hero's reward is one full Heart Container and Twinmold's Remains.

Trivia

 * Twinmold bears a striking resemblance to the Lanmola of A Link to the Past.
 * These are possibly the largest bosses Link has ever fought, along with Molgera, Stallord, Bongo Bongo, Morpheel, Eox, Cragma, and Dark Dragon.
 * One Ice Arrow to the red weak part or one Fire Arrow to the blue one will do 6 damage. Each body of the boss only has 20 HP total.
 * Oddly, there are structures bearing the image of Majora's Mask in the desert that Twinmold is fought in.