Volvagia is a fire dragon that appears in The Legend of Zelda: Ocarina of Time. He is the boss of the Fire Temple. Long before the events of Ocarina of Time, he menaced the Gorons on Death Mountain, consuming them until one Goron hero, wielding the massive Megaton Hammer, confronted and slew the beast. When Ganondorf conquered Hyrule he used the Triforce of Power to revive Volvagia with the intention of feeding the Gorons to him as punishment for refusing to accept his rule. He had three attacks. One where he would come out of one of various holes in the ground, fly up to the ceiling and send rocks plummeting down to Link, secondly he would come out and fly around breathing fire at Link. Thirdly he would partially come out to breath fire at Link.
He was defeated by using the Megaton Hammer (the treasure from the Fire Temple) on his head when he is partially out and attacking him with the sword while he is temporally stunned. Alternatively arrows can be fired at his head during the second attack. Upon defeating him the Fire Medallion was obtained as well as the fifth heart container (when collect in the order intended).
In the Ocarina of Time manga (originally released in Japan, later in America), Volvagia was initially a friend of Link's when the protagonist purchased it as a baby in Hyrule Castle Town, though in the second edition he was became influenced by Ganondorf's darkness and became evil. Link had no choice and had to fight his former friend, beheading him in the end.