Wondrous Item, legendary (requires attunement)
While wearing this amulet, you can use a bonus action to shift beyond the veil between the living and the dead. Then make a DC 18 Wisdom saving throw. On a successful check, you aren't immediately incapacitated and taken over by the will of the spirits within, for until the end of your next turn you are incorporeal and invisible. On a failure, you are taken over by the will of the amulet. You can also choose to extend it's gifts for longer and must succeed a Wisdom saving throw of increasing DC +5 for each round added.
Notes: Immunity: Necrotic, Resistance: Force, Bonus: Intelligence Saving Throws, Charmed, Cursed, Necklace, Jewelry, Sentient