Alavaster's Acidfall

A portal appears in the shape of a cylinder that is 10 feet tall with a 5 foot radius, centered on a point you can see within range. 

When you cast the spell, choose a point you can see under the cloud. Acid begins to rain down at that point. Each creature within 5 feet of that point must make a Dexterity saving throw. A creature takes 3d10 Acid damage on a failed save, or half as much damage on a successful one. On each of your turns until the spell ends, you can use your action to call down move the Acidfall in this way again, targeting the same point or a different one.

At Higher Levels. When you cast this spell using a spell slot of 4th or higher level, the damage increases by 1d10 for each slot level above 3rd.