Everburning Black Flame

Target one creature that you can see in range. You crush the bone and cause the target to erupt in unnatural black flames. The target must make a Wisdom saving throw against your spell save DC. On a failed save the target takes 4d8 fire damage and 4d8 necrotic damage. On a successful save the target takes half damage and the spell ends. At the start of the target's next turn and the start of every turn they take that the spell remains in effect they must make another Wisdom saving throw. On a failed save the target takes another 1d8 fire damage and 1d8 necrotic damage. On a successful save they take half damage and the spell ends.

If the target falls to 0 hp the spell causes the target to fail all death saves automatically as long as the spell has not ended when they would attempt the save.

The fire from this spell cannot spread to nor damage anything but the target and does no damage to the things held or worn by the target. The fire is unnatural and cannot be put out by normal means, it even burns underwater. The fire can but stopped with a dispel magic or similar spell or spell-like effect, but not magically created water.

If cast at higher levels increase the damage of both types by 1d8 per spell level on the initial hit and increase the damage of one type by 1d8 per spell level on consecutive turns.