Stallord

Twiit Fossil: Stallord is the boss of Arbiter's Grounds, Twilight Princess's fourth dungeon. Originally, Stallord is a lifeless skeleton of an ancient beast. Zant however, appears over the Stallord fossils and plunges a sword into the skull, thereafter disappearing.

Strategy
Stallord then awakens and a large sand pit forms all around him. His skeleton half protrudes from this pit sand. You have to attach your self to the edge of the pit with the Spinner and ride around it. At the right time, you detach from the wall and immediately direct yourself towards the spine. In addition, Stallord will be protected by non-agressive, yet armored zombies, called Staltroops, that will attempt to block your attacks. Avoid them or kill the ones that get in the way. After a few hits on his spine, it will crack and you will bring the Stallord down. When you hit Stallord's spine, you have to spin.

After this the head will fall to the ground, and the sand will drain out of the room. Enter the Spinner into the spinner lock in the center of the room, and spin to turn the gears. This will cause a central pillar to rise in the middle of the room. After this comes the second part of the battle.

Stallord does not die after the first round, but instead reawakens in a second form. Stallord's head will rise, and it will float around the circular room. You have to attach to the tracks along middle pillar to continually rise up it, using the Spinner. When you catch up to Stallord, you have to jump to the side wall, then back and forth while avoiding fireballs he shoots at you. Eventually Stallord's head will come off to the side, and be close enough to hit so that when you launch off the wall, the Spinner will crash into the head(the Critical Point). When the Stallord head falls down you have to strike the sword that Zant placed in the head, until it rises again and you repeat the process. The more you do this the more spike rails get in your way along the tracks. Eventually you will break the sword, setting off a chain of events which includes Stallord's destruction and the creation of a Heart Container, as a reward. You will then make your first visit to the Mirror Chamber, on the top of the Arbiter's Grounds.

On a biological note Stallord appears to be the largest creature in the Stal family, (one can assume this from the suffix of lord). It is implied by both its skull and the winglike-appendages on its back that it was once a dragon, and the spears/swords embedded in its skull, along with the Staltroop army that arises to fight with it, indicate that it was killed by an army of Hylians.

Trivia
Stallord seems to be heavily based on Volvagia for the following reasons:

They both are (or appear to be) dragons.

They both have hair.

They both have horns.

They can both breath fire.

Both Stallord and Volvagia's head is not only their main weakness, but also the last part of their bodies to be beaten.

Stallord's second phase music is a remix of the Volvagia and King Dodongo fight from OoT.

They are both brought back to life by the game's main antagonist.