You spray noxious gas in a 15-foot radius Sphere centered on a point you can see within range. The gas is Heavily Obscured. The cloud lingers in the air for the duration or until a strong wind (such as the one created by Gust of Wind) disperses it.

Each creature that starts its turn in the sphere must succeed on a Constitution saving throw or take 3d6 Poison and 3d6 Acid damage. On a successful save, creatures take half damage.

Using a Higher-Level Spell Slot. You increase either the Poison or Acid damage (your choice) by 1d6 for each spell slot level above 4.