Transfusion

You drain the blood out of a creature within range and transfuse it to yourself. The target must make a Constitution saving throw, taking 1d8 + spellcasting bonus necrotic damage on a failed save, or half as much damage on a successful one.

You heal hit points equal to the damage dealt. Excess healing is converted into temporary hitpoints.

At higher levels.
For every level above the first level, this spell does an additional 1d8 necrotic damage.