Publication:Grim-N-Gritty/Appendix 5/Armor Piercing Fang

Armor ignoring fang makes one of the subject’s natural weapons armor piercing. One-half of an opponent’s Protection applies against the damage of the attack.

The spell can affect a slam attack, fist, bite, or other natural weapon. (The spell does not change an unarmed strike’s damage from nonlethal damage to lethal damage.)