The skull whistles remind me of an experience in Central Asia. I was in an expedition camped out in the middle of nowhere, a day's drive from the nearest permanent settlement and miles from the nearest nomads. It's the middle of the night and this terrifying scream like a woman being murdered wakes me up. It was right on the edge of sounding inhuman in the same way.

The sound kept happening as I made my way down the ravine in the direction of the sound and at the bottom... Camels. Just a normal herd of camels fording the river.

There's two types of people in horror movies, the ones trying to get away from the scary things and the ones trying to get closer to the scary thing. At least you know which one you are.

Now imagine you heard that terrifying scream, followed it down the ravine, and there's a shaman sitting cross legged, looking at you unblinkingly and blowing into a human skull

You ever heard of a squirrel whistle? It mimics the sound of a squirrel in mortal distress. Used by hunters to attract … squirrels.