Enervation

Enervation was a necromancy spell that severely weakened the subject.

Effect
The caster pointed his finger and uttered the incantation, releasing a black bolt of crackling negative energy that suppressed the life force of any living creature it struck.

The spell had a chance to kill its target or it could weaken the target's offensive capability, skills and spellcasting ability. Assuming the subject survived, he regained lost power after a number of hours

If the ray struck an undead creature, it temporarily increased the creature's un-lifeforce.