The “Alien” universe is a sci-fi horror franchise centered around the terrifying xenomorph creatures. It includes the films “Alien” (1979), “Aliens” (1986), “Alien 3” (1992), “Alien: Resurrection” (1997), “Prometheus” (2012), “Alien: Covenant” (2017), and various spin-offs, video games, and tie-ins. The universe explores themes of corporate greed, survival, and the dangers of scientific exploration, all set against a backdrop of futuristic space travel.