A finger sized silver hollow tube open on both ends. A hinge runs the length on one side and a smaller hinge on the other holds the hasp closed with a small pin. The tube can be applied to the silver cord of a spiritual projection in the Astral or Ethereal Planes preventing the creature from returning to their body in the Material Plane.

Astral Body: The creature's Astral Body cannot be killed or dispelled to the Material Plane until the Hasp has been removed, or the creature's body in the Material Plane dies. The silver cord cannot be severed as it is protected by the hasp. If the Astral body is reduced to 0 Hp the creature is returned to 1 Hp next turn. A second return to 0 Hp in the same day the creature's Astral body becomes Ethereal. Creature will regain 1 Hp in 12 hours, and end Ethereal condition.  Creature regains a max of 1 hit dice per day (+2 if player not reduced to 0 Hp that day, or +1 if reduced to 0 Hp once). Max Hp of Astral body changes with and is equal to the Max Hp of the Material Body.

Material Body:  Creature's body in the Material Plane takes 1d4 damage per day while held in the Astral Plane, and reduces Max Hp by the same amount which can be regained with Greater Restoration. Greater Restoration applied in the Material plane to a trapped player removes all conditions and restores Max Hp to the Body in the Material Plane and does not transfer to the Astral Body.

Hasp Removal: Once applied to a creature's Silver Cord, the hasp is visible, but cannot be touched by anyone. Any creature connected to a hasp casting magic at their own or another attached hasp has the magic reflected randomly (roll 1d12 for directed attack with the back of the connected creature at 12'oclock) and deals 2d4 psychic damage to the creature connected to the hasp plus directed damage if hit by reflected attack. Item can be treated as an attuned cursed item. Once the curse is removed, item can be touched and removed or destroyed (AC 17 Hp 4). Greater Restoration, Remove Curse, and Dispel Magic will not resolve if the caster is connected to an Astral hasp.

Ethereal Condition: Creature with the Ethereal Condition is immune to all damage and cannot take actions or reactions. Creature is visible, but semi-transparent like a ghost. Other creatures can move through creatures and objects with Ethereal Condition as if they were difficult terrain. All items on a creature with the Ethereal condition also become Ethereal.

Scrying: Attempted scrying on a trapped creature will not resolve while scrying in the Material Plane. Scrying will resolve in the plane the trapped creature's projection resides.

Entering Another Plane: Should a trapped player cross into a different Astral Plane, the player will take 2d6 psychic damage and be rendered unconscious and ethereal for 1 day.

Feywild Time Warp: Should the player enter a time effect in the Astral Planes, the effects to the Material Body will remain with the Material time while the Astral Body will resolve under the Astral Time. (For example: the Astral time is 10 days for every 1 day in the Material Plane, the Astral Body will clock 10 days of effects while the Material Body only one.)

Associated Lore: A Night Hag commissioned this device to be made from a broken Githyanki Warrior's Silver Sword in order to trap a creature on the Ethereal Plane. The Hag would then auction the creature to either the demons for their pleasures or the Githyanki as slaves, or keep them for their own purposes. (Mod - Instead of taking damage for the Nightmare effect the Night Hag would roll 1d100 lower than the targeted creature's level to pull the creature from the Dream Plane to the Ethereal Plane to be trapped)

Notes: Healing, Control, Scrying, Banishment, Movement, Exploration, Cursed, Jewelry