Aster's magic horns

A electrified pair of curved and bejeweled horns spring from your hand to deliver a piercing force to a creature you try to hit. Make a ranged spell attack against two or one target(s). You have advantage on the attack roll if the target is not wearing armor. On a hit, the target takes 4d12 x2 force damage, and it can't take reactions until the start of its next turn. Target(s) make a Wisdom saving throw against your spell save dc. On a fail, heal 2 d6 hp and add 1 d6 +2 of lightning damage. 

The spell's damage increases by 1d12 each level.