Concussion Attack( Complete Scoundrel, p. 75)
Your attacks can damage your opponent's ability to think clearly.
Sneak attack +3d6,
Your successful sneak attack imposes a
2 penalty on the target's Intelligence and Wisdom checks, as well as on any Intelligence and Wisdom-based skill checks, for 10 rounds. If you use this feat a second time on a target before 10 rounds have elapsed, the effect of the first use expires. Using this feat reduces your sneak attack damage by 2d6.