Decaying Flames

You make a ranged spell attack at a creature by holding up the skull in its direction, sending out a beam of black iridescent light from its mouth. On a hit black ghastly flames erupt from the wound spreading around the victim causing 2d4 necrotic damage at the start of the targets turn.

If you maintain concentration, at the cost of a bonus action you cause the flames to erupt increasing the damage each time by 1d4. Each time you do this the target must succeed on a Dexterity Saving Throw against your spell DC to resist the spell. You continue to increase the damage this way to a maximum of 10d4.

When you cast this spell at higher levels the starting damage increases by 1d4 for every level past 2nd.