Angler Fish (Link's Awakening)
Link needs to climb down some stairs and then use the Flippers to dive into the Angler Fish's room. It is filled entirely with water. The Angler Fish believes that Link is food and attacks immediately after speaking. The battle itself is rather straightforward: Link must attack the Angler Fish by slashing it with his sword. To complicate things, the Angler Fish summons Angler Fries to attack him. They die in one sword hit. In addition, the Angler Fish sometimes charges at the wall and causes rocks to fall from the ceiling, which can smash into Link. Other than this, the Angler Fish primarily remains on the right side of the screen.
At the end of the battle, a Heart Container appears and sinks to the bottom of the water. Link can then climb back up the ladder and into the previous room, where a door at the north end of the room has opened. Inside he finds the Surf Harp.