Devolution

Destructive necromantic energy washes over the creature you target within range. Make a Ranged Spell Attack. On a successful hit, the creature takes 5d8 necrotic damage and the caster heals and gains Temporary Hit Points equal to half the amount of damage rolled.

The Temporary Hit Points from this spell cannot be stacked on itself, but can stack with Temporary Hit Points gained from other sources.

At higher levels. When you cast this spell using a spell slot of 5th level or higher, the damage increases by 1d8 for each slot above 4th.