This spell could be used to heal undead creatures or harm live ones. It had a range of at least 170 ft (52 m) and more experienced clerics could extend this range and cause/cure more damage. When cast, a black ray of energy from the Negative Energy plane shot out from the caster's hand at the intended target and had to succeed in making contact. A victim had a chance to resist the magic of this spell, and if successful, only received half as much damage as usual.
Only verbal and somatic components were required to cast this spell.