Drain Blood

Throw out a dark tendril of energy at a target in range. Make a spell attack against the target. On a hit, the target takes 3d6 necrotic damage. You are healed by an amount of hit points equal to the necrotic damage that the target took. 

This spell has no effect on Constructs, Undead, and any creature that does not have blood.

At Higher Levels. When you cast this spell using a spell slot of 2nd level or higher, the damage increases by 1d6 for each spell level above 1st.