4. The Thing
Clearly, this is here because of one reason: Wilford Brimley. For those weirdos who like the film for reasons other than the human/walrus hybrid, this is an excellent film to enjoy during the cold month of October. All the practical body horror effects means this film will never age, and continues to be scarier that even it's prequel that was made decades later. The concept of an alien entity that can absorb and mimic living creatures is fantastically horrible, and when you see it in action you can't help but watch through your fingers. Everyone acts rationally, no one carries the idiot-stick and yet still the world is almost destroyed because of this simple, terrifying creature in the snow.
In American cinema there are two rules of horror. Don't hurt the kid, don't hurt the animals. Well, anyone who's seen this film knows the dog scene, where one dog reveals itself to be the alien and brutally murders the rest of its horrified pack in their cell. This is totally not cool, and Kurt Russell was right to run in there with a flamethrower. Why you gotta hurt the dogs man?
Modern horror movies have a trend of re-releasing themselves in black and white because they claim it amplifies the horror. Films like this are the reason directors got that into their heads. You can't have Halloween without zombies, and you can't have zombies without this film. No explanation of where they come from, and really no lead up; they just show up randomly at the start of the film and keep coming. George A. Romero introduced us to the concept that zombies are a perfect backdrop to human horribleness, and we not only see victims ripped to shreds by the undead, but humans ripped apart by other humans. Racism, distrust, prejudice... and lots of blood. If you've enjoyed the last few years of "The Walking Dead" on TV (and I know that you have) then you can thank this film. Do it, I'll wait.
The sad part is of course the very end. Our hero, a black man that unfortunately remains a progressive casting choice to this day, emerges alive after surviving the night in the title. He is greeted by humans who are taking back the world from the living dead, and is immediate shot dead. Did they think he was a zombie, or did they see he was black and decided to take the opportunity to act out their racism? The film doesn't spoon-feed you the answer, but I think we all know the answer. Happy Halloween.