"The thing" is an apt title for the monster in the film, because it does not take on a definitive form; it is always changing. What's more the form into which it is changing is you, that is whenever the monster contacts one of the Arctic researchers of the film, it can imitate their form. And here we see the central conceit of the film: The monster could be in any one of the people on screen. Who are we to trust? Who are we, even more importantly, not to trust? And ultimately, is the monster present within us at all times?Thus, all of the characters are faced with an interesting ethical conundrum, are the bonds of friendship and personal affection enough to overcome the monster inside of us all? To make matters worse, the entire film takes place in a barren and frozen landscape, the cast of characters are devoid of civilized contact. In many ways this film echoes, in a more horrific manner, the social realities espoused in works such as Lord of the Flies. This film is, most certainly not bound to the 1980's in fact, it proves more successful, both as a horror film and as a sweeping social commentary, than most horror films of our day.
Disclaimer: This is disturbing, and by that I mean: Great fun!