Flaying Strike (3.5e Maneuver)

Even the barbarian seemed a little squicked as you tore into the opponent with such savagry that when you were done, their skin was tatters hanging off their exposed flesh.

You brutally flay an opponent's skin with a vicious attack. You make a melee attack and deal an additional +10d6 damage, and the opponent loses 2d8 points of natural armor bonus (to a minimum of 0 natural armor). The natural armor remains lost until the target is completely healed of all damage, recieves a regenerate spell which cures the effect in 1 round, or makes a Heal check as a full round action, DC 15 + your initiator level. The torn skin leaves the victim in terrible pain, they take a -2 penalty to attack as long as their condition persists.

A successful Fortitude save DC 17 + Str modifier negates the penalty to attack rolls from pain and halves the loss of natural armor.