Blight Fog

Area of Effect: Sphere, 20-ft. radius

You create a thick, gray, 40-foot cloud of deadly mist at a point you can see. The mist is deadly to plants; normal plants wither immediately upon being touched by the fog. Each plant-based creature that begins its turn in the cloud or enters the cloud takes 5d6 + 20 necrotic damage, or half damage with a successful Constitution saving throw. The magic is specifically designed to affect plants; it has no effect on other creatures.

The cloud moves away from the caster at 10 feet per round. It is dispersed by moderate wind (10 mph or greater). The area of the mist is heavily obscured.