Probably the absolute classic of weird Christmas based cinema. If not one of the absolute classics of weird cinema anyway. Often listed as one of the worst movies of all time, for me Santa Claus Conquers the Martians is a must see midnight movie for Christmas Eve. It's become a tradition in my house, whether anyone likes it or not.
Made famous to the masses as an MST3K movie, the movie is a work of unabashed surreal genius by director Nicholas Webster. That has become a major cult Christmas classic, spawning a comic book by Dell Comics, a novel and theatre productions based on it. The movie fell into public domain, and so has become a movie that has been shown time and time again on cable horror host shows, and online, as well as being shown on cult cinema nights across the planet as their cult Christmas movie of choice.
Making Santa Claus Conquers The Martians one of the greatest Christmas movies ever, in my opinion.
Weird Retro Fact: You can read the whole of the comic book version of Santa Claus Conquers The Martians on our Weird Retro facebook archives.