Death Knight Unholy Armor

This ancient Necromantic spell transforms a portion of the recipient's life force into an unearthly, phantasmal suit of armor. This spectral armor then absorbs the damage from any attack directed at its wearer for a limited amount of time. As the magiks that link this armor to its host cease, so will the invulnerability that it grants.

Unholy Armor's main weakness in the short time that it lasts. Often what the enemy will do is see Unholy Armor, run until the spell wears off and you're left with a unit with 1/2 hit points.

Another major weakness with Unholy Armor is that units can still be Polymorphed. The main use of Unholy Armor is on Death Knight before you send him in to use Death and Decay.

You can also cast Unholy Armor on Demolition Squads and Goblin Sappers to blow them up.

Unholy Armor is good for killing enemy Flying Machines. Cast it on Flying Machines and Goblin Zeppelins and their hit points will be cut in half. when it wears off, the enemy units will be easier to kill.