Nightwalker Amuletwondrous, rare (requires attunement)

This amulet is carved from black horn and it’s centerpiece is a brilliant black opal that never feels hot, nor cold, to the touch.
To attune to this amulet you must endure its effects for at least 4 rounds without falling unconscious. Once attuned however, you can breathe while wearing it, and as a bonus action can activate or deactivate it’s Void’s Grasp effect.

Void’s Grasp

Creatures that end their turn within 5 feet of the amulet must succeed on a DC 14 Constitution saving throw or begin suffocating. Suffocating creatures can survive a number of rounds equal to their Constitution modifier before they drop to 0 hit points. This effect ends when the creature starts its turn farther than 5 feet from the amulet, or when it drops to 0 hit points. Creatures that do not need to breathe are immune to this effect.

amulet, necklace