8. Lifeforce (1985)
In theory, this sounds good, a science fiction premise for vampires as creatures from outer space. Astronauts finding a ship in Halley's comet. A plague breaking out in a London. Okay, these now sound familiar, but there doesn't appear to be any reason why it cant be a fun movie. And then you watch it and things start going wrong. Like Ghost Story, this is another novel adaptation, The Space Vampires by Colin Wilson, where several things got lost in translation. For example, Cannon Films thought that the original title sounded too like an exploitation film and then has the female vampire played by Mathilda May spend the film naked for no adequately explained reason. However, there is still the potential for an interesting horror film within the material, it just needs to be executed in a different way.