Argorok

From Zelda - Wiki on Neoseeker

Argorok's Concept Art

Argorok is a boss featuring in The Legend of Zelda: Twilight Princess. He is the boss of the very long dungeon: City in the Sky, and terrorized the Ooccaa there. Even though he is the seventh boss in the game, he isn't very difficult, as the tactic to defeating him is simple.

Defeating the Boss

Argorok, even though you would expect differently, is actually a not-so-hard boss. The key to defeating him is slashing a glowing "wound" on the top of his body, with your sword, this will be exposed in Stage Two of the fight.

Stage One

As soon as you get to the boss door, open it, then clawshot to some vines outside (Heal up if you wish before, this is the only fight in the game minus Ganondorf that does not automatically start). Then, (After climbing) Argorok will surface ready to fight, using your Double Clawshots climb one of the poles. When you get to the top, clawshot onto his tail (Which is a clawshot target) and put on your iron boots. The boss will be weighed down to the platform, and fall down loosing some of his armour. Repeat this step, before a cutscene and stage two of the fight begins.

Stage Two

Argorok using his Flamethrower.

You will see some Peahats have risen to the top of the stage, these will help you. Again, climb the poles with Clawshots, and then near the top clawshot to one of the Peahats. Argorok should begin by now shooting his flamethrower, which will knock you down loosing a heart if hit. To avoid, keep Z-Targeting the next peahat, and pressing A. As soon as he stops, get behind and aim with your pointer at his body. Clawshot onto it and begin slashing, before he comes back down to the platform. Repeat this twice to kill, but on your third round when you are on the Peahats he may suddenly turn round and start his flamethrower on your aiming side, forcing you to clawshot the other way. When you finish him, you are rewarded with a Heart Container, and the last Mirror Shard.