You create a whirling siphon of necrotic energy that can suck the life force out of living creatures.  Roll (12d8); the total is how many hit points of creatures this spell can affect.  Each creature in a 60 ft. cone originating from yourself can be affected by this spell.  You may divide the amount of hit points the spell can affect among the creatures in any way you like.  This spell has no effect on undead or constructs.  

When dividing the damage among the creatures, each creature within the cone must have at least 3 HP of damage designated to it.  No creature in the area of effect can take no damage, unless the creature is a construct or undead.       

A creature takes necrotic damage equal to the number of hit points you designated to that creature.  After resolving the damage, you regain hit points equal to half the amount of hit points the spell affected. 

At Higher Levels.  When you cast this spell using a 8th level spell slot or higher, roll an additional 2d8 for each spell slot level above 4th.