Caustic Bomb

You form a small glob of concentrated acid in your hand that you then launch at a target within range. The glob explodes on impact into a cloud of caustic fumes. Each creature in a 20-foot-radius sphere centered on that point must make a Dexterity saving throw. A target takes 8d6 acid damage on a failed save, or half as much damage on a successful one.

The acidic cloud spreads around corners and lingers for 1 minute unless it's blown away by high winds or an equivalent spell. Any creature that begins or ends its turn in the cloud must make a Constitution saving throw or take half of the damage rolled. 

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, the damage increases by 1d6 for each slot level above 3rd.