Blood Siphon

You touch a creature with the tip of your finger and attempt to siphon their life force to strengthen your own. Make a melee spell attack against a target, with a successful attack dealing 1d8 necrotic damage and granting you half of the damage dealt as temporary hit points.

The spell's damage is increased by 1d8 when you reach 5th level (2d8), 11th level (3d8), and 17th level (4d8).