Now get out of the temple

Since water is now flowing through the area, the bridge is raised for you to cross. There is a closed gate on the other side of the bridge for you to open. Open the gate by standing on the dale, then without moving, hit the target on the back wall with the clawshot. Swing through the gate before it closes to find a chest containing a heart piece. Hit the target on the ceiling again to go back through the gate into the stairway area. You can grab a red rupee by jumping into the water and swimming to the platform in the center of the room. Use the big key to open the door to the boss area. Drop down the hole in the center and prepare for action.

Put on your Iron Boots to sink and meet your enemy. Gear up with your clawshot and drag the boss to you by hitting one of the eyes inside the tentacles. Strike the boss a few times with your sword but he is not going to be thrilled by this move. The goon sends some evil beings after you. To eliminate them, drag them towards you with the clawshot and throw them away so they explode. Use the clawshot to drag the big boss towards you yet again. Now this dude is really mad as he reveals himself to be a large swimming monster. Take off your Iron Boots and swim after him, hitting him with the clawshot again. Much like washing your hair: Claw, Slash, Repeat a couple more times and you will win the fight. After the victory you are rewarded with the Fused Shadow and Heart Container. Now get out of the temple.