Columbia Pictures
If you grew up in the '80s (in which case you definitely remember these TVs), chances are that you watched "The Real Ghostbusters", the animated cartoon that followed the 1984 live-action "Ghostbusters", on your family's classic '80s television set. And who could forget Slimer (voiced by Frank Welker), the naughty green ghost that practically served like a ravenous pet at the Ghostbusters station? Well, apparently, almost everybody who was involved in the making of the 1989 sequel, "Ghostbusters II."
According to Dennys McCoy, who was a writer on the ABC series, the entire sequel was initially written and shot without including Slimer at all. In a 2023 interview with Den of Geek, McCoy said, "If you notice in "Ghostbusters II," they have all these little incidental scenes where Slimer appears. Well, the thing is, they did the entire movie without Slimer." Director Ivan Reitman (whose son, Jason, continued the franchise after his death) and the rest of the "Ghostbusers II" only considered adding the supernatural rascal once the animated show's creators, Joe Medjuck and Michael C. Gross, pointed out that he was the most popular and beloved character in the series.
Despite the inclusion, Slimer didn't get much screen time in the sequel
Columbia Pictures
Although the "ugly little spud" eventually made it into "Ghostbusters II," his role was significantly reduced. That's because viewers in the preview screenings found the ghost's scenes with Rick Moranis' Louis Tully "too intrusive." As Michael C. Gross explained (via Industrial Light & Magic), "There were a lot of kids who loved to see him, so we knew we could not abandon him completely, but he never really worked with the audience the way we expected."
Thus, the initial plan to give Slimer a bigger role in the sequel was nixed, and most of the sequences featuring him ended up on the editing room floor. Overall, Slimer briefly appears twice in the blockbuster — both times sharing the screen with Tully and freaking him out — and popping up once more during the end credits. It's really a shame that they couldn't really maximize his potential in the movie, since the hideous little creature is by far one of the most entertaining characters in the animated show. The recurring gags between Slimer and Dave Coulier's Peter Venkman are both hilarious and sweet, and the film could've easily implemented them in a similar way, but in the end, it wasn't meant to be.