This can be cast on a single unengaged enemy model within 12" of the caster (you can even pick a character inside a unit, a war machine crew, or choose to hit the character or monster/chariot he is riding, etc). The victim must immediately take a Toughness test. If failed, the model is crushed to death (remember a roll of 6 is always a failure and models without a Toughness value fail only on a 6). No Armour saves or Ward saves are allowed.