Head Shot( Complete Scoundrel, p. 77)
By striking at your opponent's head, you can temporarily disrupt his thought processes.
Weapon Focus (PH) (any bludgeoning weapon) , Sneak attack +6d6,
Your successful sneak attack with a bludgeoning weapon for which you have selected Weapon Focus leaves your foe confused for 1 round. A successful Will save (DC 10 + the number of extra damage dice normally dealt by your sneak attack + your Dex modifier) negates this effect. If you use this feat a second time on a target before 1 round has elapsed, the effect of the first use expires. Using this feat reduces your sneak attack damage by 5d6.
You must be able to reach your foe's head to use this feat with a melee attack.