Grappling Hook

The Grappling Hook is an item created using a Hook and three Iron Chains. When used, the Grappling Hook will extend, latching onto anything it can reach; if it goes too far, it will retract. The player will be pulled onto the wall and will be stuck there until they jump or use the Grappling hook on another block, allowing for easier placement of torches. The player should take care not to hang for too long - after 60 seconds of hanging, the player will fall off, similar to the Ivy Whip. If you press space bar, you will jump off. It is easy if you jump, then aim at a wall and click. This is a way to easily get up mineshafts faster. The Grappling Hook is currently used in the crafting recipe for the Ivy Whip, an upgraded version of the Grappling Hook.

In Patch 1.0.6 (Unreleased) There will be a hotkey for using the Grappling Hook and Ivy Whip

TIP: For players underground, the grappling hook is great to hook yourself to the ground directly beneath you so if you are attacked by an enemy, you will not be flung off the platform you are on.

Trivia
The tooltip added in 1.0.4 to the Grappling hook may be a reference to Mortal Kombat.