SRD:Disruption

Disruption: A weapon of disruption is the bane of all undead. Any undead creature struck in combat must succeed on a DC 14 Will save or be destroyed. A weapon of disruption must be a bludgeoning weapon. (If you roll this property randomly for a piercing or slashing weapon, reroll.)

Strong conjuration; CL 14th; Craft Magical Arms and Armor, heal; Price +2 bonus.