Black Serpents

You send of a serpent formed from writhing black fire. Choose six 5ft. cubes in any contiguous shape within range. Each creature in that area must make a Dexterity saving throw. A target takes 8d6 Fire damage on a failed save, or half as much damage on a successful one. Either way a creature loses maximum hit points equal to half the damage they take. These hit points can only be restored after completing a long rest, or with a greater restoration spell.

At Higher Levels. When you cast this spell using a spell slot of 5th level or higher, the damage increases by 1d6 for each slot level above 4th.