Slimer, originally referred to as "Onionhead" and sometimes "the Mean Green Ghost" and "Ugly Little Spud", is a character from the Ghostbusters franchise. He appears in the films Ghostbusters (1984), Ghostbusters II (1989), the remake Ghostbusters (2016), and Ghostbusters: Frozen Empire (2024), in the animated television series: The Real...
No good trouble-maker.