Oh boy, where do I start? 'Plan 9 from Outer Space' is a SF/horror film written, produced and directed by Edward D. Wood, Jr. in 1958, and released in 1959. It is officially the leading contender for the title of "worst movie ever made" and has earned Ed Wood a posthumous Golden Turkey Award as the worst director of all time. The film boasts an appalling script, unconvincing special effects, and multiple production errors visible even in the final version of the film.
The story of the making of 'Plan 9' was recently made into a film of its own by Tim Burton, entitled 'Ed Wood'. Burton's film was critically hailed, which was more that Wood's films ever were.