Toxic Cloud

You create a 20-foot-radius sphere of poisonous gas centered on a point you choose within 90 feet. The cloud spreads around corners, and its area is heavily obscured. It lasts for 1 minute or until a strong wind disperses it. Each creature that starts its turn in the cloud must make a Constitution saving throw, taking 4d8 poison damage on a failed save, or half as much damage on a successful one.