In an interview in Starlog 148 (published November 1989), MacNicol revealed that in the original script for Ghostbusters II (1989), the character of Janosz Poha was a rather lackluster villain called Jason. It was MacNicol who suggested to Ivan Reitman and Harold Ramis to make the art restorer come from Carpathia, linking him to the painting of Vigo. During filming, MacNicol spent a lot of time in his trailer, creating Janosz' origin and accent, as well as a mythology for Carpathia. He even came up with his own vision for a Carpathian flag, which featured a snake stepping on a man.

Acting is a kind of madness. A managed madness. As we strive for emotional truth in our playing, we must necessarily reach down into scarred-over wounds, and feel the old pains, over and over again.