Ghostbusters (1984)

Three university parapsychologists lose their research grant and their credibility when the Dean decides that their theories, methods and conclusions have no place in his august institution. Out of a job, they decide to go into business for themselves, setting up as professional supernatural eliminators. Starting out with only a converted fire station and a beat-up ambulance to their name, the Ghostbusters quickly become local heroes when the city sees a dramatic rise in paranormal activity and a giant marshmallow threatens its very existence.