Donut's War Crime

you deal 1d20 fire damage and 1d20 acid damage to all creatures regardless of immunities or resistances and 1d12 of each per turn until the spell is dispelled through such spells as dispel magic, or counterspell. the targets make a Constitution saving throw at the start of each of their turns before they take the damage. if they succeed on that save, they take half damage from THIS SPELL ONLY, THAT TURN ONLY