Demon Fire Snap

You snap your fingers and a bolt of green demon fire zips to the target. Make a ranged spell attack against the target. On a hit, the target takes 3d8 +3 necrotic damage. 

Before your snap occurs, sacrifice movement next turn do add 2d8 Necroctic damage

This spell's damage increases by 1d8 when you reach 6th level (4d8), 11th level (5d8), and 17th level (6d8).