You create a cloud of infectious miasma in a 5-foot cube you can see within range. The area is lightly obscured and lasts for the duration or until a wind of moderate or greater speed (at least 10 miles per hour) disperses it.

Any creature that starts its turn in the area or enters it for the first time on a turn must succeed on a Constitution saving throw or be poisoned until the start of its next turn. While it is poisoned in this way, it can't speak or breathe.

Undead, constructs, and creatures that don’t need to breathe automatically succeed on the saving throw. The spell's effect on creatures counts as a disease.