Wolf Savage

While using Wolf Style, when you deal at least 10 points of damage to a prone opponent with a natural weapon or an unarmed strike, as a swift action you can savage that creature. When you do, your opponent must succeed at a Fortitude save (DC = 10 + half your character level + your Wisdom modifier). If the target fails the saving throw, it takes either 1d4 Charisma damage or 1d4 Constitution damage, or it becomes fatigued (your choice). Ability score damage dealt with this ability cannot equal or exceed the victim's actual ability score total.