Alien is a science-fiction horror film series centered on the deadly xenomorph creature and the struggle of humans, especially Ellen Ripley, to survive encounters with it. The franchise began with Ridley Scott's original film and expanded into sequels, prequels, comics, novels, and games. It is one of the most influential and recognizable sci-fi horror properties in cinema, known for its tense atmosphere, iconic creature design, and themes of survival, corporate greed, and isolation.