In the season 2 finale, "Storytelling," an unhinged Lottie continues to push her plan to enact another ritual sacrifice to appease "It," the It that, to her, was always out there, demanding blood in exchange for sustenance. The rest of the women sense Lottie's volatility and play along as to not upset her. Things keep going, and going, and going in the direction of an earnest restaging of their old hunts, in which the unlucky Yellowjacket who pulls the ominous queen of hearts is hunted, killed, and cannibalized by the rest.
Van and Taissa were supposed to have called psychiatric services to scoop up Lottie, but out of a sense of guilt ("She's like this because of us," Van says), they cancel the call, and decide to help her themselves. But things escalate quicker than anyone can control, and when Shauna pulls the queen, the rest don masks, take up knives, and assume the old position. "You know there's no 'It,' right? 'It' was just us!" Shauna cries in fear. Lottie responds: "Is there a difference?"
This is the most clarity we've gotten thus far on the supernatural vs. sadly natural debate. What happened in the woods so profoundly traumatized these women that questions of cause have become moot. Survival became an act of such intense self-annihilation that a word like "supernatural" actually loses its meaning. Of course it was supernatural. Having to murder and eat your friends to stay alive is so far beyond the bounds of "natural" that it makes a murderous antler-crowned queen that dictates all the terrible things you do actually seem quaint. It is in fact a preferable alternative to choosing irredeemable violence.
The surviving Yellowjackets have finally come face to face with the ultimate truth: they were the monsters all along.