John Carpenter's "The Thing" {1982}

A group of scientists at a remote Antarctic outpost are threatened by an alien life form that inhabits its victims. Soon the men are overcome by fear and paranoia: who is still human and who is possessed by “The Thing?” Got off to a slow start at the box office, but, thanks to a huge fan following and critical reassessment, is now considered a modern horror classic. (“Man is the warmest place to hide.”) Rated R