Epic Blast Fireball

A brilliant streak flashes from your outstretched hands to a point you choose within range, and then blossoms with a crescendoes roar into a massive explosion of flame. Each creature in a 200-foot-radius sphere centered on that point must make a Dexterity saving throw. A target takes 56d6 fire damage on a failed save, or half as much damage on a successful one.

The fire spreads around corners. It ignites flammable objects in the area that aren't being worn or carried.

When this spell is cast, the casters hands are burnt to the point of being unable to cast somatic spells until a Greater Restoration is cast on their hands.