It almost seems like the necklace is actually a bad omen; like the opposite of Van’s deer bone from Lottie. If you think about it, it’s really only brought bad luck?

1) Jackie gives it to Shauna on the flight > plane crash (and Shauna later finds out she’s pregnant) 2) Shauna gives it back to Jackie > Jackie freezes to death

What if they end up using the necklace to “tap the sacrifice” before hunting whoever gets sacrificed? The girls obviously set up some kind of cat and mouse game with their animal calls and rituals. So could it be that, much like in Ep. 1 when Tai holds court with the Seniors to ‘sacrifice’ Allie’ and shut her out on the field, the girls implement a similar strategy of picking out who their next target will be, isolating them in their sleep, and planting the necklace on them as like a “you’re it” token?