Stunning Fist

You must declare that you are using this feat before making your attack roll (thus, a failed attack ruins the attempt). Stunning Fist forces a foe damaged by your unarmed attack to make a Fortitude save (DC 10 + 1/2 your character level + your Spt modifier) in addition to dealing damage normally. Defenders who fail their saves are stunned for 1 round (until just before your next action). For the effects of being stunned, see Chapter 13: Abilities and Conditions, "Conditions," Stunned. You may attempt a stunning attack once per day for every four levels you have attained (see "Special," below), and no more than once per round. Constructs, oozes, plants, undead, incorporeal creatures and creatures immune to critical hits cannot be stunned.