A plume of jet-black magically-corrupting smoke swirls in a cylinder centered on a point that you can see within range before vanishing. The cylinder can have up to a 30-foot radius and be up to 60 feet high, and the smoke spreads around corners. Each creature in the area must make a Constitution saving throw. On a failed saving throw, a creature takes 7d8 poison damage and is poisoned for the duration. On a success, it takes half as much damage and isn't poisoned.

While a creature is poisoned by the spell, it is blinded and its speed is halved. It repeats the saving throw at the end of each of its turns. On a failure, it takes 7d8 poison damage. On a success, it is no longer poisoned.

The spell treats immunity to poison damage as if it were resistance to poison damage. Creatures that are normally immune to being poisoned can be poisoned by this spell, but they have advantage on its saving throws.