Fear and Loathing in Athas
Powerful Breakage: When you roll maximum on a damage roll, your weapon has a chance to break. Thus a critical hit is not subject to this unless you are using a high crit weapon. You must then roll a d20 and on a result of a 5 or lower, the weapon breaks. There will be a rider effect to the subject from such a mighty blow should the weapon break. This rider will be determined by the damage and weapon type.