Necrotic skull bomb

Necrotic skull bomb was a necromancy spell that imbued a humanoid skull with negative energy. The skull could then be thrown as a projectile that would burst upon impact, releasing the energy stored within.

Effects
Any living creature caught within the blast of a necrotic skull bomb was drained of their life force in a similar manner to the spell energy drain. If they survived the initial effects they would slowly regain their energy over the course of a number of hours, depending on the skill of this spell's caster.

This spell had a different effect on the undead, making them more robust for the duration of an hour.

Casting
In addition to verbal and somatic components, this spell required the skull of a humanoid creature.