Dretch‘s Fetid Cloud

Fetid Cloud: A 10-foot radius of disgusting green gas extends out from the dretch. The gas spreads around corners, and its area is lightly obscured. It lasts for 1 minute or until a Strong Wind disperses it. Any creature that starts its turn in that area must succeed on a DC 11 Constitution saving throw or be Poisoned until the start of its next turn. While Poisoned in this way, the target can take either an action or a Bonus Action on its turn, not both, and can't take Reactions.