Homunculus

While the monster is on the same plane of existence as its master, the two of them can communicate telepathically with each other.

. Hit: damage, and the target is subjected to the following effect.
Constitution Saving Throw: DC .
Failure: The target has the Poisoned condition until the end of the homunculus's next turn.
Failure by 5 or More: The target has the Poisoned condition for 1 minute. While Poisoned, the target has the Unconscious condition, which ends early if the target takes any damage.