Whip

In Spirit Tracks, the Whip is an item obtained in the Ocean Temple. Its main use is to swing from poles similar to the Grappling Hook from The Wind Waker and for puzzles found in certain dungeons that require the transfer of certain swords from one place to another. Moreover, it can also be used to remove thorns from thorn trees that block Link's path as well as being able to hold on to flying propellers located within the Ocean Temple to travel to otherwise unreachable areas. This is also useful when Link plays the "Song of Birds" on the Spirit Flute to summon birds. By doing so, the young hero can use the Whip to latch on to a wooden bar that the animals are holding, which allows him to be carried by the birds to certain areas.

The Whip does have a use as a weapon, as it can attack certain ChuChus that Link could not attack with his sword alone and it can take the shields and armor away from certain enemies.

The Whip is used in the Whip Race minigame located in Whittleton.

The Legend of Zelda: Skyward Sword
The whip is also an availible item that was demonstrated at E3's press confrence.

Trivia

 * The Whip seems reminiscent of the Rope, a snake like enemy appearing in early Zelda games. It also shares similarities with the Rope Snake, an item that appears in the Nintendo game Mother 3, as well in Super Smash Bros. Brawl, used by Lucas.