Ray Stantz alluded to this event, the undersea, unexplained mass sponge migration (at which he was present) as a retort to Peter Venkman; who chided Ray that there was little evidence of the Paranormal.
We later learn that the sponges migrated 'about a foot and a half', which leads us to believe that it was not as paranormal as Ray thinks.
- Originally, Ray's line was about a "multiple high-altitude rockfall". Dan Aykroyd had to rerecord the line in a postproduction looping session, where he came up with "mass sponge migration." 
- ↑ Shay, Don (November 1985). Making Ghostbusters, p. 25 annotation. New York Zoetrope, New York NY USA, ISBN 0918432685. Paragraph reads: "A similar problem plagued Stantz' "multiple high-altitude rockfall" reference. However, since this bit of dialogue was included in a long shot of the actors, Reitman and his editors were able to rerecord the line and insert it into the soundtrack during a postproduction looping session. Dan Aykroyd came up with his own replacement: "Of course you forget, Peter, I was present at an undersea, unexplained mass sponge migration.""