vengeful tempest

A churning storm cloud forms centered on a point above you and spread to a radius of 500 feet. Lightning flashes in the area, thunder booms, and strong winds roar. Each creature under the cloud (no more than 100,000 feet beneath the cloud) when it appears must make a Constitution saving throw. On a failed save, a creature takes 20d20 thunder damage and becomes deafened, blinded, frightened, and exhausted for 24 hours.

Each round you maintain this spell, the storm produces different effects on your turn.

Round 2. Acidic rain falls from the cloud. Each creature and object under the cloud takes 20d20 acid damage.

Round 3. You call 100 bolts of lightning from the cloud to strike 100 creatures or objects of your choice beneath the cloud. A given creature or object can't be struck by more than one bolt. A struck creature must make a Dexterity saving throw. The creature takes 20d20 lightning damage on a failed save, or half as much damage on a successful one. (you also create any effects mentioned in all previous rounds.)

Round 4. Hailstones rain down from the cloud. Each creature under the cloud takes 20d20 bludgeoning damage. (you also create any effects mentioned in all previous rounds.)

Round 5–10. Gusts and freezing rain assail the area under the cloud. The area becomes difficult terrain and is heavily obscured. Each creature there takes 20d20 cold damage. Ranged weapon attacks in the area are impossible. Finally, gusts of strong wind (ranging from 100 to 200 miles per hour) automatically disperse fog, mists, and similar phenomena in the area, whether mundane or magical. (you also create any effects mentioned in all previous rounds.)

Round 11. spheres of annihilation plummet from the cloud and deal 20d20 fire damage in an 80-foot sphere. (you also create any effects mentioned in all previous rounds.)

if you choose to continue this spell, all effects from every previous round are produced every round until it is dispelled.