Wondrous Item, very rare (requires attunement by a by a Cleric, Druid, Shaman, or Lupine)
While you wear this amulet, as a reaction, you can drag a creature that you can see, and that is prone, into the shadows beneath them for 1 turn. While within the shadows, the creature is considered to be in an alternate plane of existence and cannot be affected by any creatures or spells (short of a Wish spell), not in the same plane. At the end of the creature's next turn, they exit the shadow.
Notes: Set: Constitution Score, by a Cleric, Druid, Shaman, or Lupine, Buff, Jewelry