Cloudkill

You create a 20-foot-radius Sphere of yellow-green fog centered on a point within range. The fog lasts for the duration or until strong wind (such as the one created by Gust of Wind ) disperses it, ending the spell. Its area is Heavily Obscured.

Each creature in the Sphere makes a Constitution saving throw, taking 5d8 Poison damage on a failed save or half as much damage on a successful one. A creature must also make this save when the Sphere moves into its space and when it enters the Sphere or ends its turn there. A creature makes this save only once per turn.

The Sphere moves 10 feet away from you at the start of each of your turns.

Using a Higher-Level Spell Slot

The damage increases by 1d8 for each spell slot level above 5.