Acid Rain

5th-level conjuration (elemental)
Casting time: 1 action
Range: 150 feet
Target: Each creature within 20 foot wide, 30 feet high cylinder from a point you can see
Components: V, S, M (a drop of acid)
Duration: Concentration, up to 1 minute
Classes:
Subclasses:

You unleash a storm of swirling acid in a cylinder 20 feet wide and 30 feet high centered on a point you can see. The area is heavily obscured by the driving acidfall. A creature that starts its turn in the area or that enters the area for the first time on its turn takes 6d6 acid damage, or half damage with a successful Dexterity saving throw. A creature takes half damage from the acid (as if it had made a successful saving throw) automatically at the start of its first turn after leaving the affected area.

At Higher Levels. When you cast this spell using a spell slot of 6th level or higher, the damage increases by 1d6 for every slot level above 5th.