Inflict Critical Wounds

Necromancy
Level: Clr 4, Destruction 4
Components: V, S
Casting Time: 1 standard action
Range: Touch
Target: Creature touched
Duration: Instantaneous
Saving Throw: Will half
Spell Resistance: Yes

When laying your hand upon a creature, you channel negative energy that deals 4d8
points of damage +1 point per caster level (maximum +5).

Since undead are powered by negative energy, this spell cures such a creature of a
like amount of damage, rather than harming it.