Bash

You may attempt a Bash as a full attack action with a bludgeoning weapon. If the attack hits, roll damage normally; the foe struck by your attack must then attempt a Fortitude save (DC 10 + the damage rolled). The foe takes no damage from the blow, but if he fails the save, he is stunned for 1 round (see Chapter 13: Abilities and Conditions). You can use Bash only once per round and no more than once per level per day. When you use Bash, you forfeit any bonus or extra attacks granted by other feats or abilities (such as the Cleave feat or the bloodlust spell). Creatures immune to critical hits cannot be stunned.