The Alien (also known as a Xenomorph XX121 or Internecivus raptus, or simply a xenomorph)[1][2][3][4] is a fictional endoparasitoid extraterrestrial s...pecies that serves as the titular antagonist of the Alien film series. The species made its debut in the film Alien (1979) and reappeared in the sequels Aliens (1986), Alien 3 (1992), and Alien Resurrection (1997). The species returns in the prequel series, first with a predecessor in Prometheus (2012) and a further evolved form in Alien: Covenant (2017).[5] It also featured in the crossover films Alien vs. Predator (2004) and Aliens vs. Predator: Requiem (2007), with the skull and tail of one of the creatures respectively appearing briefly in Predator 2 (1990) and The Predator (2018), and will return in the FX television series Alien (2023). In addition, the Alien appears in various literature and video game spin-offs from the franchises.