Acid Fog

You create a 20-foot-radius sphere of viscous, acidic fog centered on a point within range. The sphere spreads around corners, and its area is heavily obscured. It lasts for the duration or until a wind of severe or greater speed (at least 31 miles per hour) disperses it.

Creatures moving through the fog move at half their normal speed and take a -2 penalty on all melee attack and melee damage rolls. The vapors completely prevent effective ranged weapon attacks (except for magic rays and the like).

A creature or object that falls into the fog is slowed so that each 10 feet of vapor that it passes through reduces the falling damage by 1d6.

When the cloud appears, each creature and object in it takes 4d6 acid damage. A creature also takes this damage when it enters the spell's area for the first time on a turn or ends its turn there (uncarried objects take this damage at the start of each of your turns).

At Higher Levels. When you cast this spell using a spell slot of 7nd level or higher, the radius of the fog increases by 20 feet for each slot level above 6th.