Megaton Hammer
The Megaton Hammer is a massive hammer that allows Link to smash enemies and hit the ground. It was first utilized by the Hero of the Gorons in order to slay the dragon Volvagia.[1][2]
The Hammer is a rather slow weapon, but can be used in place of the Master Sword and Biggoron's Sword. Due to its large size, however, Link must use both hands and is open to attack as a defense item cannot be used. Its main use is to smash Rusty Switches as well as Red Boulders found throughout Hyrule and in particular on Death Mountain. The Megaton Hammer also performs many of the same functions as Bombs with its ability to break impeding boulders.
This item is found in the Fire Temple, the fifth dungeon of the game. Link uses this item to slay Volvagia once more and send the demon to the world of the dead where it belongs. Darunia is subsequently revealed as one of the Seven Sages, the Sage of Fire.