Thermoplastic Blast

You create two forces of extreme cold and heat and force them together, creating a thermoplastic explosion with a radius of 40ft. Creatures within this radius must make a Constitution saving throw, suffering 12d8 fire damage, becoming deafened and knocked prone on a failed save. On a successful save, they take half damage. After casting this spell, the affected radius is lightly obscured in steam for 1d4 rounds, and a creature entering the steam for the first time or ending its turn there suffers 4d6 fire damage.