other two films are the remake of Invaders from Mars and The Texas Chainsaw Massacre 2. Before Hooper was finally approved, Michael Winner was offered the chance to direct the film. It has been suggested that Lifeforce is largely a remake of Hammer Film Productions's Quatermass and the Pit. In an interview, director Tobe Hooper discussed how Cannon Films gave him $25 million, free rein, and Colin Wilson's book The Space Vampires. Hooper then shares how giddy he was: "I thought I'd go back to my roots and make a 70 mm Hammer film." Screenplay The screenplay was written by Dan O'Bannon and Don Jakoby (both would also collaborate with Tobe Hooper in Invaders from Mars). Hooper came up with the idea of using Halley's Comet in the screenplay, rather than the asteroid belt as originally used in the novel, as the comet was going to pass by Earth one year following the film's release. The time settings were also changed from the mid-21st century to the present day. Michael Armstrong and Olaf Pooley were brought on during production to perform uncredited rewrites, Armstrong acting as a liaison between Hooper and the art department. Hooper later said, "The spirit of the book is certainly there from my interpretation of the reading. Though Colin Wilson's novel was set in the future, I made it a contemporary piece for identification. Also, I tied in Halley's comet, where they make the find of the alien ship. It has been millions of years in the coma of Halley's comet, traveling as a parasite of sorts. But, basically, I think the movie embodies the same spiritual feeling that Colin Wilson intended." Colin Wilson was unhappy with the way the film turned out. He wrote of it, "John Fowles had once told me that the film of The Magus was the worst movie ever made. After seeing Lifeforce I sent him a postcard telling him that I had gone one better." Hooper later said "Lifeforce had a great look but lacked a screenplay. There wasn't a hell of a lot that could be done about that except to change it completely. The film started off as Space Vampires, and that's actually what it should've been called. With that title you'd look at that picture with a completely different set of sunglasses!" Casting In February 1984, Billy Idol said he had been offered a lead role as