Corroding Fog

You create a 20-foot-radius sphere of orange, corrosive gas centered on a point within range. The cloud spreads around corners, and its area is heavily obscured. The cloud lingers in the air for the duration.

Each creature that is completely within the cloud at the start of its turn must make a Constitution saving throw against acid. On a failed save, the creature takes 3d6 Acid damage and half as much on a successful one.

A moderate wind (at least 10 miles per hour) disperses the cloud after 4 rounds. A strong wind (at least 20 miles per hour) disperses it after 1 round.