Blight Bolt

Drawing from your own essence, you launch a bolt of necrotic energy at a creature you can see within 90ft. At the cost of 1 Hit Point, make a Ranged Spell Attack, on a hit, the target takes 1d8 Necrotic damage, and you gain Temporary Hit Points equal to your Proficiency bonus.

Cantrip Upgrade. The damage increases by 1d8 when you reach levels 5 (2d8), 11 (3d8), and 17 (4d8). The Temporary Hit Points increase by your Spellcasting Modifier once you hit level 15.