Type: Ambush
Sources: Complete Scoundrel
Your attack can weaken your foe's resistance to magic.
Prerequisite: Sneak attack +4d6, Knowledge (arcana) 1 rank.
Benefit: Your successful sneak attack reduces the target's spell resistance and power resistance by 5 (minimum 0) 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 4d6.