I don't even know if you guys are ready for this shit.

In late January, 1959, a group of ten friends (mainly students), all experienced cross-country skiiers, embarked on a trek in the northern Ural mountains, heading for a peak called Otorten. On the second day of the journey, one of the members of the party, Yuri Yudin, became ill and had to turn back. The other nine continued on. Heavy snowstorms and poor visibility caused them to lose their bearings, and rather than taking their original route through the pass, they found themselves on the east shoulder of Kholat Syakhl, known by the indigenous Mansi people as "Mountain of the Dead." The group decided to set up camp there the night of February 2nd and wait out the storm. They snapped some photos, they huddled in their tents. No one knows exactly what happened next.

Searchers found the abandoned camp several weeks later. The tents had been ripped open from within, suggesting that the skiiers were gripped by a sudden hysteria and fled in the night. "Traces from the camp showed that all group members left the camp of their own accord, on foot." The search party followed a set of footprints and discovered the bodies of five of the campers hundreds of meters away in a wood. All were only partially dressed—in their underwear, some with only one shoe, some wrapped in shreds of clothing apparently ripped from their dead and dying comrades. Searchers found the remains of a fire under a large pine tree on the wood's edge. Three of the corpses near the pine tree "seemed to have died in poses suggesting that they were attempting to return to the camp."

The remaining four campers weren't found until May, their corpses "under four meters of snow, in a ravine in a stream valley further into the wood from the pine tree."

According to the formal inquest:

Three of them had fatal injuries: the body of Thibeaux-Brignolle had major skull damage, and both Dubunina and Zolotarev had major chest fractures. The force required to cause such damage would have been extremely high, with one expert comparing it to the force of a car crash. Notably, the bodies had no external wounds, as if they were crippled by a high level of pressure. One woman was found to be missing her tongue. There had initially been some speculation that the indigenous Mansi people might have attacked and murdered the group for encroaching upon their lands, but investigation indicated that the nature of their deaths did not support this thesis; the hikers' footprints alone were visible, and they showed no sign of hand-to-hand struggle.

The final verdict in the inquest was that the skiiers had died because of a "compelling unknown force." In the aftermath, some family members claimed that the skiiers' skin had a bizarre orange tan, some said the corpses showed signs of high levels of radiation exposure, and other hikers reported seeing "strange orange spheres in the night sky to the north" on the night of the incident. There was talk of a Soviet coverup. But nobody really knows what happened on Kholat Syakhl.

“If I had a chance to ask God just one question, it would be, ‘What really happened to my friends that night?’” said Yury Yudin, the only member of the skiing expedition who survived.

Best. Mystery. Ever.

(Makes me think of this.)
(Oh, and here's a no-fun website that debunks everything and attributes the skiiers' panic to an infrasound phenomenon. Zzzzzzzzzzzzzz.)