Wondrous Item

Rare

This glass orb has a special funnel at its top that traps bad dreams. When you finish a long rest in which you sleep while the orb is on your person, there is a 25 percent chance that the orb is filled with a small amount of dark, swirling smoke: a visual representation of a collected nightmare. The orb can collect 1 nightmare every 24 hours and can hold up to 10 nightmares in this way.
 You can use an action to throw the flask at a point you can see within 30 feet of you, shattering and destroying it upon impact. When the flask shatters, each creature within 20 feet of the point must succeed on a DC 13 Wisdom saving throw or be magically put to sleep. If a creature has less than half its hit points left, it makes the saving throw with disadvantage. Each creature that falls asleep is unconscious for up to 1 minute or until it takes any damage other than psychic damage or someone uses an action to shake or slap the sleeper awake. A creature that's asleep in this way takes 1d10 psychic damage at the start of each of its turns, up to a number of turns equal to the number of nightmares collected by the orb. This psychic damage can't reduce a creature's hit points below 1.
  Alternatively, the orb can be used as a preventative measure against the dream spell. When you're targeted by the dream spell, the caster of the spell must make a DC 17 Wisdom saving throw. On a failed save, the caster takes 1d10 psychic damage for each collected nightmare in the flask. The flask then cracks and is destroyed, and the spell fails. On a successful save, the spell takes effect, and the orb isn't destroyed.