Acidic Shroud

You conjure a cloud of corrosive mist in a 20-foot radius centered on a point within range. The mist clings to creatures, slowly eating away at their defenses. Each creature in the area when the spell is cast, or that enters the area for the first time on a turn, must make a Dexterity saving throw. On a failed save, a creature’s armor or natural defenses are weakened, causing their AC to be reduced by 2 for the duration of the spell.