Witch Pox

A beam of wicked, green energy slithers out toward a creature within range, forming a fell connection between you and the target. Make a ranged spell attack against that creature. On a hit, the target takes 1d6 poison damage and must make a Constitution saving throw. On a failed save, the creature is poisoned, and on each of your turns for the duration, you can use your bonus action to deal 1d4 necrotic damage to the target automatically. The spell ends if you use your bonus action to do anything else. The spell also ends if the target is ever outside the spell’s range.

The spell's initial damage increases by 1d6 and subsequent damage increases by 1d4 when you reach 5th level (2d6, 2d4), 11th level (3d6, 3d4), and 17th level (4d6, 4d4).