If you haven’t seen it, They Live concerns a conspiracy whereby aliens have infiltrated our lives, only regular people have no idea - the invaders have a clever cloaking device that means we just see them as normal folk.
But then the central character discovers that by wearing special glasses, he sees the world for how it really is (well, in black-and-white), unmasking the creepy freaks (clearly inspired by the Topps Mars Attacks! cards, predating Tim Burton’s movie).
Especially fun is the printed matter found in everyday life; through the lenses, you read what’s really written (Click the image abovefor a full-sized version and spot how many things are littered with the subliminal messages).
Carpenter was never very subtle with social commentary, but this isn’t a subtle movie - it’s great, comic-book action with clever ideas. The only director coming close to this kind of movie these days is Robert Rodriguez.
BONUS: Geek Trivia - The immortal line “I have come here to chew bubble gum and kick ass, and I’m all out of bubble gum” was not in the script; star and former pro-wrestler Roddy Piper ad-libbed it on the day.