Acid Rain

Until the spell ends, acid rain falls in a 40-foot-tall cylinder with a 40-foot radius centered on a point you choose within range. The area is lightly obscured, and exposed flames in the area are doused.
Chemical pools accumulate on the ground in the area, making it difficult terrain. When a creature enters the spell’s area for the first time on a turn or starts its turn there, it takes 3d6 acid damage and must make a Dexterity saving throw. On a failed save, it falls prone in the pools, taking an additional 3d6 acid damage. 
At Higher Levels. When you cast this spell using a spell slot of 6th level or higher, the acid damage increases by 1d6 for each slot level above 5th.