There have been three such movies made, all (to one extent or another) based on a science fiction short story titled "
Who Goes There," by John W. Campbell. That's a great read, by the way. I've read it several times over. Always chilling.
There's a short story based on "Who Goes There," (titled
The Things ) also, that takes the same exact story line, but tells it from the viewpoint of the alien. That's a great read, too.
The above reminds me that there's another great read for fans of
Beowulf, written from the perspective of Grendel, the monster who was eventually defeated and killed by Beowulf. Well worth a read. Short book.