Dangoro

The Dangoro is a giant Goron who will not let you pass into the next room. He will start by bringing down the magnetic platform down into the lava. The next thing he will do is come after you slowly. Equip your Iron Boots and your sword so you can be ready. Once he starts to swing in for a punch, slash at his belly until he falls down. Right after he does this, he will roll up into a ball and roll straight at you. Make sure you're near an edge then grab him like you would a goat to throw him behind you. Throw him into the lava three times to defeat him and you can receive the Hero's Bow. Oddly, if you return to the mini-boss area Dangoro will not be there.

Trivia

 * The battle is somewhat similar to Super Mario 64's Bowser Battles.