Acid fog

You create a 5-foot-radius sphere of highly acidic fog centered on a point within range. The fog spreads around corners making it difficult terrain, and its area is heavily obscured. It lasts for the duration or until a wind of moderate or greater speed (at least 10 miles per hour) disperses it.

When a creature enters the spell's area for the first time on a turn or starts its turn there. The creature takes 2d6 acid damage. Creatures are affected even if they hold their breath or don't need to breathe. Any object in the area also takes the damage.

At Higher Levels. When you cast this spell using a spell slot of 3rd level or higher, the radius of the fog increases by 5 feet and the damage by 1d6 for each slot level above 1st.