SRD:Momento Mori

As a free action that counts as a quickened spell, the character wills the target dead without a word or gesture. The character’s thought snuffs out the life force of a living creature of 160 or fewer HD, killing it instantly. The subject is entitled to a Fortitude saving throw (DC 30 + relevant ability modifier) to have a chance of surviving the attack. If the save is successful, the target instead takes 3d6+20 points of damage.