Alien: Romulus is a breakout hit new addition to the Alien franchise - and now that film has a prequel story that reveals what happened to the original Xenomorph from Ridley Scott's Alien (1979) movie. If you don't know: Alien began with the story of commercial space liner the Nostromo being diverted to the planet LV-426 to investigate a distress signal. There they find an alien spacecraft (Engineers) containing parasitic lifeforms that attack one of the crew, infecting him with a xenomorph. Officer Ellen Ripley (Sigourney Weaver) was the only survivor of the creature's subsequent infiltration of the Nostromo; she blew the ship up and blew the Xenomorph out of the airlock of her escape craft vessel. But that's not where the story ended...
The opening scene of Fede Álvarez's Alien: Romulus saw the Weyland-Yutani corporation finally locate the wreckage of the Nostromo nearly a quarter century after its destruction. The survey team also found a cocoon-like rock in the wreckage, which the confirmed as the remains of the original Xenomorph that attacked the Nostromo (designated "XX121"). The specimen is taken back to the Remus/Romulus space station, to be examined by science officer Rook in the lab on Remus.
(SPOILERS FOLLOW!)
Marvel Comics' new Alien: Romulus #1 prequel comic reveals that, as always in the Alien franchise, conspiring and backstabbing are the true cause of the disaster that unfolds. A pair of security guards named Adrian and Hyla are very much against XX121 being on Remus - especially Hyla, who lost an eye on a previous mission battling hostile alien species. Rook and the Remus scientists take the precaution of keeping the xenomorph sample on a cryogenic bed to ensure stasis - but that is not a detail Adrian and Hyla know when they eventually sneak into the lab and try to eject the xenomorph off the station. When two security troopers cut off the cryo-bed, XX121 is revived and gets right back on its job: killing off entire crews, starting with Adrian. Chaos breaks loose and facehugger specimens engineered on Remus get loose, infecting various science personnel - if XX121 doesn't murder them first.
The ending of Marvel's Alien: Romulus prequel comic sees Hyla and Rook in a race to their respective objectives: Hyla wants to purge open the airlocks and suck the xenomorph back into space; Rook needs to ensure the completion of the Prometheus serum developed from the creature, before destroying it. In the end, Hyla battles and fatally wounds XX121 with a barrage of gunshots, ending the creature for good. Unfortunately, Rook doesn't shut the airlock in time and Hyla gets sucked into space along with the rest of the crew, while Rook marvels at the Prometheus compound, and the test mouse it has revived.
Now we have the official canon story of how Alien's (1979) iconic Xenomorph met its end - and how that ending began the events of Alien: Romulus.
Alien: Romulus is available to watch on streaming. You can purchase the comic at Marvel.