Disrupting Weapon

(Player's Handbook v.3.5, page 223, DnD 3.5)

Transmutation

Level: ; Cleric 5; Hunter of the Dead 4; Knight of the Weave 5
Components: V, S
Casting Time: 1 standard action
Range: Touch
Target: One melee weapon
Duration: 1 round/level
Saving Throw: Will negates (harmless, object); see text
Spell Resistance: Yes (harmless, object)

This spell makes a melee weapon deadly to undead. Any undead creature with HD equal to or less than your caster level must succeed on a Will save or be destroyed utterly if struck in combat with this weapon. Spell resistance does not apply against the destruction effect.