Alchemical Storm

Create a 40-ft. radius storm of volatile reagents centered on a point within range. When you use this power, choose acid, cold, fire, lightning, poison, or thunder. When a creature enters the area for the first time on a turn or starts its turn there, it must make a DEX save, taking 36 (8d8) damage of the chosen type on a failed save, or half as much on a success. As a bonus action on later turns, you may change the damage type.