King Dodongo, also known as the Infernal Dinosaur, is the second primary boss in The Legend of Zelda: Ocarina of Time and The Legend of Zelda: Ocarina of Time 3D, where you can find him in Dodongo's Cavern. He's taken over the cavern in which the Gorons got their prominent source of nutrients and food. Before Link entered, the Gorons were famished and desired the enter the cave once more, though not only did the Dodongos that infested the area pose a major threat, though the evil Gerudo tyrant Ganondorf blocked the entrance by placing a large boulder in front of it.
Once the game's protagonist, Link, comes in possession of the Goron's Bracelet, he'll be able to pick up a Bomb Flower and lodge it at the large rock. It'll explode, thus giving him access to the cavern. His next goal was to enter the cave and search for King Dodongo.
He eventually came upon him, and in order to thwart him he was required to use his Bomb Bag to toss bombs inside of King Dodongo's mouth when he was sucking in, reading to blow fire. This would stun him for a short time, allowing the player to go in and slash him with your sword. Following this attack, King Dodongo would crawl up in a ball and cruise around the course, attempting to hit you. After crashing into two walls, he'd repeat the process of sucking in, and the player was thus required to toss more bombs in his mouth once more.
In The Legend of Zelda: Four Swords Adventure, the boss appeared once more, and the tactic to defeat him was very similar.