With a gentle patter, corrosive raindrops build to an acidic deluge in a 20-foot-radius, 60-foot-tall cylinder, centered on a point within range. When the rain begins, each creature in the area must make a Dexterity saving throw, taking 4d6 acid damage on a failure or half as much damage on a success. For the duration, a creature must also make this saving throw when it enters the spells area for the first time on its turn or ends its turn there.