Cloudkill

Create a 20-ft. radius sphere of yellow-green fog centered on a point within range. The fog is heavily obscured and lasts until dispersed by strong wind or until the effect ends. A creature makes a CON save when the fog moves into its space, when it enters, or when it ends its turn there, taking 5d8 poison damage on a failed save, or half on a success. The sphere moves 10 ft. away from you at the start of each of your turns.