Need help finding this long ago watched thriller/horror movie

Looking for help identifying a movie from the following scene descriptions.

Located at some sort of isolated winter arctic outpost. where a team of workers one by one get turned into demons with a mark then showing on their foreheads and their speech gets lower. One scene where a technician tapes a wireless camera to an remote controlled toy truck and slowly navigates it down into an underground ice cave, where the head demon has an altar with a woman to sacrifice. One guy covers his forehead with a hat to pretend he is normal, but when it accidentally falls off he says ‘whoops’ in that lower voice with a smile on his face. Really cool thriller/horror film. Anyone know the title?


Just a guess, maybe?:

Arctic/Antarctica, ice, remote outpost, possession, altar.