Alien

Carpenter's film was made in the window Alien opened, and reviewers at the time treated them as siblings: an isolated crew, no way out, a creature that uses the bodies it kills, and practical effects designed to be looked at rather than glimpsed. The shared ancestor matters too. Both descend from Campbell's Who Goes There? by way of the 1951 film, and O'Bannon acknowledged the 1951 version among Alien's sources, so this is partly a family resemblance. Filed MEDIUM for exactly that reason: what Alien supplied was commercial permission and a standard for creature work, not the story, which Carpenter had from Campbell.

Alien exists because Dan O'Bannon was dissatisfied with this one. He co-wrote and shot Dark Star with John Carpenter, and its alien is a painted beach ball played for laughs; he has described wanting to do the same premise, a small crew alone with a creature, and make it genuinely frightening instead. Three things carry straight across:

• A bored, bickering blue-collar crew rather than officers, which is the tone Alien is famous for
• A confined ship as the whole world, with no rescue available
• A creature loose in the air ducts, staged in Dark Star as farce and in Alien as the hunt

This is also the route by which Jodorowsky's Dune reached Alien. O'Bannon did effects on that abandoned 1975 production and met H. R. Giger there, then brought Giger to Ridley Scott. That production was never finished, so the line to Alien runs through the people who worked on it rather than through the film itself.

Alien was pitched as Jaws in space, and that was not a critic's summary but the line used to sell it. Everything structural came with the phrase:

• The creature is withheld for most of the running time and glimpsed in pieces
• The first victim establishes the rules and is somebody the audience had started to like
• Working people in a confined vessel, arguing about money, with no authority coming
• A company or a mayor who knew and decided the risk was acceptable

The graph already holds 2001 and Dark Star pointing at Alien, for the ships and for the crew. This is where the horror grammar came from.

2001 established the used, industrial spacecraft that Alien took as its starting point and then made shabby. Kubrick's ships are clean and corporate; Ridley Scott's Nostromo is the same design language after twenty years of wear, with crew who complain about shares rather than marvel at the void. The silent exteriors and the slow docking grammar carry over intact.

Dan O'Bannon acknowledged the Lovecraft debt, and the derelict is where it shows:

• An abandoned structure built by a vanished species, entered by a small expedition
• Its architecture is the exposition: the crew read the dead pilot rather than being told about it
• Both stories put their horror in what the builders were fleeing, not in the builders

Ridley Scott has named Tobe Hooper's The Texas Chain Saw Massacre as an influence on the look and tension of Alien: a small group picked off one by one in a hostile place, and horror built on dread and grime rather than on showing the monster.

Dan O'Bannon modelled the creature's life cycle on parasitic wasps, which lay their eggs inside living hosts that the larvae then eat their way out of, the chestburster's biology.