(8 SoulThreads) Each creature in a 60-foot-radius sphere from a point within 150 feet must make a Constitution saving throw, taking 8d10 necrotic damage on a failed save, or half as much on a success. Any creatures killed in this way have their souls utterly destroyed, so you cannot consume them.
You then get a potion that, when drunk by or fed to a creature as an action. causes that creature to regain hit points up to half the total necrotic damage dealt and cure a single poison or disease affecting it.