Aykroyd wrote the script, intending to star in it alongside Eddie Murphy and his close friend and fellow "Saturday Night Live" ("SNL") alumnus John Belushi, before Belushi's accidental death in March 1982. Aykroyd recalled: "I was writing a line for John, and and talent agent Bernie Brillstein called and said they just found him … We loved each other as brothers." He turned to another "SNL" former castmate, Bill Murray, who agreed to join the project, albeit without an explicit agreement, which is how he often worked. Aykroyd pitched his concept to Brillstein as three men who chase ghosts, and included a sketch of the "Marshmallow Man". He likened them to normal pest control workers, saying that "calling a Ghostbuster was just like getting rats removed." Aykroyd believed Ivan Reitman was the logical choice to direct, based on his successes with films like "Animal House" (1978) and "Stripes" (1981). Reitman was aware of the film's outline while Belushi was still a prospective cast member, and it took place in the future with many groups of intergalactic ghostbusters. He felt it "would have cost something like $200million to make." Aykroyd's original 70- to 80-page script treatment was more serious in tone and was intended to be scary.