Splinter Spell Resistance

You create an aura around the target weapon that weakens a foe's magical defenses. The first time each round the weapon damages a creature with spell resistance, that creature's spell resistance is reduced by 5 for 1 round. This reduction is not cumulative for multiple attacks within the same round, even if the target is struck by different weapons, each affected by a different casting of splinter spell resistance. However, the same creature's spell resistance can be reduced on multiple rounds by subsequent hits.