Ghostbusters is a 1984 American supernatural comedy film directed by Ivan Reitman and written by Dan Aykroyd and Harold Ramis. The film stars Bill Murray, Aykroyd, and Ramis as three eccentric parapsychologists in New York City who start a ghost catching business. Sigourney Weaver and Rick Moranis co-star as a potential client and her neighbor. The Ghostbusters business booms after some initial skepticism, but when an uptown high-rise apartment building becomes the focal point of spirit activity linked to the ancient god Gozer, the problem threatens to overwhelm the team and the entire world.
Originally intended by Aykroyd as a project for himself and fellow Saturday Night Live alumnus John Belushi, the film had a very different story during initial drafts. Aykroyd's vision of "Ghostmashers" traveling through time, space, and other dimensions to fight large ghosts was deemed financially impractical by Reitman. Based on the director's suggestions, Aykroyd and Ramis finalized the screenplay from May-June 1982. They had written roles specifically for Belushi, John Candy, and Eddie Murphy, but were forced to change the script after Belushi died and the latter two actors would not commit to the film.