Sea Urchins are only found along the beaches in the southwest corner of Koholint Island and they are extremely easy enemies to avoid. They will lie stationary on the ground and the only way you will take damage from one is if you walk into it. They are also very weak, and will die with one slash of your sword. To get past an urchin, either push it away with your Shield or simply kill it with your Sword.
Sea Urchin Sprite from Link's Awakening.
- "Sea Urchins live in the Great Sea surrounding Koholint Island. When they wash up on shore, their spiky bodies can make travel along the beach quite treacherous." — (The Great Hyrule Encyclopedia).