The River of Slime (also known as Psychomagnotheric Slime Flow) appears and is talked about in great detail in Ghostbusters II. Later in Ghostbusters: The Video Game, the River of Slime's origins and purpose are expanded upon.
Ghostbusters: The Video GameEdit
In the 1920s, the Cult of Gozer created a strain of Ectoplasm later known as Psychomagnotheric Slime. They pumped the slime past the Hudson River into New York City's decommissioned New York Pneumatic Railroad. It was intended to provide more power to Gozer upon its arrival.
Gozer never got the chance to draw power from the River of Slime. Five years after Gozer's defeat, the River came under the control of Vigo. He used the power generated from the negative emotions of New York City citizens to try and resurrect himself in the body of a child. Ray Stantz discovered the River but was almost pulled in. He later found it again on foot with Egon Spengler and Winston Zeddemore. When Winston tried to take a measurement, he was pulled in. Egon and Ray jumped in after him. They rode the flow of the river straight to the Manhattan Museum of Art.
- In the Ghostbusters II August 5, 1988 draft, the River of Slime is not present. Instead, Ray and Egon fall into a slime pit full of bugs and rodents.  
- In NOW Comics The Real Ghostbusters starring in Ghostbusters II part 1 the river of slime along with the Psychomagnotheric Slime sample in the court room is green and not pink.
- In NOW Comics The Real Ghostbusters starring in Ghostbusters II part 2 and NOW Comics The Real Ghostbusters starring in Ghostbusters II part 3 it is suggested to be pink like the film.
- ↑ Aykroyd, Dan & Ramis, Harold (1988). Ghostbusters II (August 5, 1988 Draft) (Script p. 63). Paragraph reads: "Their skin and clothing are caked with mashed bugs and some sort of foul muck."
- ↑ Aykroyd, Dan & Ramis, Harold (1988). Ghostbusters II (August 5, 1988 Draft) (Script p. 64). Ray Stantz says: "I fell into a slimepit full of bugs and rodents. Spengy had to pull me out."