Very Rare Poison (Inhaled)
Nightmare. When a creature is subjected to Dreaming Death, they have to make a Wisdom saving throw (DC 17). On a failed save they fall into a magical slumber. The creature falls unconscious for the next hour, during which they experience horrible visions and nightmares. At the end of each of their turns, they take 3d4 Psychic damage and they can repeat the saving throw, waking up and ending the effect on a succes. The sleeper is not awoken by the damage they take from this poison, but can be woken when they take damage from something else, or someone uses an action to shake or slap the sleeper awake.