Boomerang

Now that's what we call an upgrade! Instead of the old single-lock-on boomerang, Wind Waker gives players the ability to lock onto five different targets at once. When thrown, the boomerang will automatically go after each target in the order you acquired them.

The Boomerang is an important item for both combat and puzzle solving. It can be used while on the boat as well.

• Combat: The Boomerang is the tool of choice against small foes and most flying and water-based enemies. It will instantly knock out rats, Morth spike balls, Keese bats and make Peahats drop out of the sky (and kill them with a second hit), but it doesn't have any effect on Bubble skulls, for example. It can also be used to stun opponents, such as Bokoblins, ChuChus, and others, instantly rendering them vulnerable to your attacks while they're seeing stars. The Boomerang can be used for one-off hits (lock on, throw) or to take out or stun larger groups of enemies (switch to first-person view, manually lock on to up to give targets, throw).
• Switch Activation: Use the Boomerang to activate crystal switches by locking on to them first. Sometimes, it's necessary to trigger multiple switches in short succession, which is only possible by locking on to all switches with the Boomerang in the right order. Note that the Boomerang cannot be used to activate eye switches.
• Cutting: The Boomerang will cut vines, tentacles, and certain ropes if you are able to lock on to them in first-person mode. You can sever vines holding up platforms this way, for example.
• Item Retrieval: The Boomerang can lock onto pots, orbs, and items, including rupees, bombs, hearts, and arrows (but not weapons) and bring them back to Link. This maneuver is extremely handy when you're trying to grab some power-ups from an orb left on the ocean surface from the safety of your boat. You have to hurry up when locking on to items as they soon start to fade and disappear. The moment the Boomerang makes contact with an item (even if it is about to be gone), it's secured.