Volvagia

A legendary, snake-like dragon in Goron lore, Subterranean Lava Dragon: Volvagia (灼熱穴居竜ヴァルバジア, Scorching Hot Cave Dwelling Dragon: Varubajia) is the boss residing in the Fire Temple. Volvagia was an ancient dragon that lived in the depths of the fiery Death Mountain, long before Link was born. It was said that a legendary Goron destroyed Volvagia with the use of the Megaton Hammer. By the time of Ocarina of Time, Ganondorf had revived the fierce creature to secure the corrupted Fire Temple from intrusion and by feeding the native Gorons to Volvagia, to "make an example" to other people that might revolt against him. Incited by Darunia's son, Link set on to destroy Volvagia or else; if the dragon escaped from the temple, Hyrule would become a burning wasteland. In the game, Volvagia is referred to as "it" with a single instance in which its gender is specified as male.

Barba
Volvagia bears a remarkable resemblance to Barba, a dragon boss in The Adventure of Link. Not only in appearance, but in name as well. Volvagia's Japanese name is "Varubajia" and Barba's "Barubajia". In Japanese, the "B" is often used instead of "V" because the "V" sound is not natural to the language.

Strategy
The battle is a lot like "Whack-a-Mole" because there are nine holes, and Link must whack the dragon when it comes out using a hammer. On the battle field, there are pits of fire that Volvagia bursts out of to attack Link. His head will pop out from one of the pits. Look for one pit that is spitting fire, which is a telltale sign that this pit is the one he will most likely come out from. However, do not venture too close to the pit as he swings his fire hair around to cause damage. Once Volvagia comes out of one of the nine pits, he would do one of three attacks: (1)Come out halfway of his pit, (2)Rise out of the pit he comes from and hovers above the stage, chasing after Link, or (3)fly up to the ceiling of the cave. When Volvagia comes out only halfway, he will do one of two things, depending where Link is at the moment. If Link is far away, he will breathe fire. If Link is up close to him, he will try to slash him. Link must get close to him and strike Volvagia's head with the Megaton Hammer. Once stunned, Link can slash him with the Master Sword or hit him on the head again with the hammer until Volvagia recedes back into his pit. Eventually, he will leave his pit and attack Link out on the field, flying through the air. As said before, he will either cause rocks to fall down at Link (watch the shadows of the falling rocks to avoid them), or he will follow him and try to burn him. Link can use his arrows at that point to fend Volvagia off or he can go to the edge of the battle stage and hang there while the rocks fall down. Try to pierce him under the chin with the arrow shots.

After four smacks with the Megaton Hammer and four slashes with the Master Sword, the almighty dragon is defeated and the Gorons are saved. Watch as his body burns into a skeleton and his skull crashes to the ground. It will move its jaw one last time and burn up, rewarding you with a Heart Container and a very pleased Darunia.

In the Manga
In the Ocarina of Time manga, Volvagia is a dragon that Link bought as a young child. When he returned 7 years later, Volvagia was corrupted by Ganondorf, requiring Link, begrudgingly, to kill it. Volvagia is also able to talk in the manga, although only the word 'Link'. Before his dying breath, tears drop from Volvagia's eyes and he sadly utters "Li...nk...."

Trivia

 * Along with King Dodongo (with whom Volvagia shares its battle music), Volvagia is one of the two normal bosses in Ocarina of Time to have a different battle theme.