Sci-fi writer/director Dan O'Bannon was as involved in John Carpenter's first film, Dark Star, as Carpenter himself. He's ubiquitous in the credits and was even supposed to be given co-director credit, but that title when to Carpenter alone.
When the movie premiered, it was a great disappointment to O'Bannon, who famously remarked: "It was supposed to be the greatest student film ever made and it ended up being the least impressive feature film ever made." But the movie inspired Dan to try his hand at writing a horror version of Dark Star and that film, after a side trip through Jodorowsky's ill-omened Dune, led to Ridley Scott's iconic 1979 film, Alien (written by O'Bannon).
In this CinemaTyler video, he looks at O'Bannon's career trajectory from Dark Star through Dune to Alien and how O'Bannon would also serve as a strange attractor in bringing with him the artists to Alien (H.R. Giger, Ron Cobb, and Chris Foss) who would give it its unprecedented and hugely influential mood and style.