5. Close Encounters of the Third Kind 2: Night Skies

Close Encounters of the Third Kind is a sensitive, serious and optimistic take on alien invasion, not unlike its director's other movie,
War of the Worlds, which depicts an all out war between man and Martian on a devastating, explosive scale, as seen through the eyes of earth's favourite everyman (?) Tom Cruise. You'll know
Close Encounters for the mashed potato mountains and that memorable little keyboard tune. Given the movie's huge success back in in '77, Columbia decided that they wanted to cash in, because that's what movie studios do. Steven Spielberg didn't like this idea, because he's a man with a bit of integrity, but the director still didn't want the studio to make a sequel without his involvement. So he got going on something called
Night Skies, which was going to be the more horror-aligned sequel to
Close Encounters, in which an innocent family are tortured by little green aliens. Though production design begin on
Night Skies, the idea was eventually scrapped (because it completely undermined the peaceful aesethics of the original) and was, instead, split into three separate movies:
E.T.:
The Extra-Terrestrial, Poltergeist and
Gremlins, all of which came out great. So for any movie executives reading this: if you have any sequels in the works, split them into three, individual movies and see what happens with that instead. You never know.