Bash

You can declare a bash attempt before taking a full attack action with a bludgeoning weapon. For the successful attack of your choice, roll damage normally. The foe struck must make a Fortitude save (DC 10 + the damage rolled). The foe takes no damage from that blow, but on a failed save is stunned for 1 round (cannot act, loses any Dexterity bonus to AC, and takes a −2 penalty to AC). 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 Cleave or haste). Constructs, oozes, plants, undead, incorporeal creatures, and creatures immune to critical hits cannot be stunned.