Location:
End of Dungeon 2: The Moon.
Attack Pattern:
Dodongo patrols the room in a set path. It is immune to sword attacks unless stunned. It will occasionally open its mouth.
Weakness:
Bombs. When its mouth is open, it can swallow a Bomb, which will stun it and make it vulnerable to sword attacks.
Strategy:
The key to defeating Dodongo is using Bombs. Wait for Dodongo to open its mouth, then quickly place a Bomb directly in front of it. If timed correctly, Dodongo will swallow the Bomb, causing it to explode internally and stun it. While stunned, quickly attack Dodongo with your sword. You'll need to repeat this process several times. Ensure you have a good supply of Bombs before entering this fight. If you run out, you'll need to exit the dungeon and purchase more. Be careful not to get too close when it's not stunned, as it can charge at Link.
Reward:
Heart Container, Triforce of Wisdom Piece 2.