Amaterasu

Target one creature of your choice within sight. That creature needs to make a Dexterity saving throw or start becoming engulfed by black flames. These flames can’t be put out by water, only dispel magic or remove curse. The black flames deal 1d6 of fire damage at the beginning of the afflicted creatures’  turns. The caster can choose to put out the flames as an action. If the afflicted creature dies while burning, they turn to ash upon death and can only be resurrected by a true resurrection or wish spell.