The Cursed Necklace is an amalgamation of the Odd Necklace and Cursed Hand twists, which appeared in Survivor: Last Leap. The twist added two new Individual Immunity necklaces into the game, which hold the same power as a standard one, but with it's next owner chosen by the most recently eliminated castaway.
The Cursed Necklace guarantees the possessor safety from a single Tribal Council of their choice. The identity of the holders (one for each tribe) is always known and it does not work like a hidden immunity idol. The owner must explicitly state they want to use it before or in the early hours of Tribal Council. Once someone has used the Cursed Necklace at Tribal Council, the person voted out at that Tribal gets the power to decide who gets to have the Cursed Necklace next (although it cannot be the person who has just used it). If the voted off player does not re-assign the necklace is time, the host reserves the power to give the necklace out by other means. The last use of the Cursed Necklace was at the Final 8.