Dretch

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.

Constitution Saving Throw: DC 11, each creature in a 10-foot Emanation originating from the dretch. Failure: The target has the Poisoned condition until the end of its next turn. While Poisoned, the creature can take either an action or a Bonus Action on its turn, not both, and it can’t take Reactions.