Ocarina of Time
King Dodongo is the boss of Dodongo's Cavern in Ocarina of Time. It was sent to the Cavern by Ganondorf, he feeds on the Gorons that try to enter. Link can defeat him by running around the perimeter of the area and throwing a Bomb into his mouth when he inhales oxygen before he exhales flames. This will stun him, giving Link the opportunity to slash away at the large beast's head. This process takes about three times to complete. After the third and final time, he will roll into the pit of lava and perish. Afterwards, Link will be rewarded with the Goron's Ruby by Darunia, and also receive a Heart Container.
Four Swords Adventures
King Dodongo is the boss of the Realm of the Memories stage.