The Chosen One's Storm

An ancient demon spell is casted.  A churning storm cloud forms, centered on a point you can see and spreading to a radius of 85 feet. Lightning flashes in the area, thunder booms, and strong winds roar. Each creature under the cloud (no more than 5,000 feet beneath the cloud) when it appears must make a Constitution saving throw. On a failed save, a creature takes 3d4 Bludgeoning damage and becomes deafened for 2 minutes.

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

*ANY ALLY OR ENEMY CAUGHT IN THE STORM WILL BE AFFECTED UNLESS SAVED BY A SAVING CONSTITUTION THROW.

Round 2. Acidic rain falls from the cloud. Each creature and object under the cloud takes 1d6 acid damage.

Round 3. You call six bolts of lightning from the cloud to strike six 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 2d20 lightning damage on a failed save, or half as much damage on a successful one.

Round 4. Demonic Magic is at work, this makes any creature targeted take 2d20 Necrotic Damage. Saving throw is CHA, if saved creature takes Half Damage.