Plunge

Plunge is Infantry's unique skill that can be unlocked for 7 coins. Plunge gives Infantry the ability to launch themselves off a cliff with the maximum height of 2 blocks onto a tile, dealing significant damage, knocking back and stun any enemy on said tile. Plunge will often leave enemies stunned, making them vulnerable to be finished off if the damage isn't enough.

Plunge can be upgraded to level 2 for 10 coins, dealing more damage, usually enough to kill Brutes. For 14 coins, you can upgrade Plunge to level 3, Plunge can be used from any height.

Once used in battle, Plunge will automatically recharge over time until it can be used again. A small icon of the skill will appear over the commanders unit for a short amount of time, when the ability has been recharged.

Link
*Source: http://badnorth.wikidot.com/plunge