The Real Ghostbusters Cereal Ad 1989

"Ghostbusters Cereal was a cereal brand that was in production from 1985 though 1990. However, the name of the cereal changed based on which franchise item was prevalent.
It began based on Ghostbusters the first film. Later it was renamed The Real Ghostbusters, to promote with the cartoon series. The cereal had "fruit-flavored O's and marshmallow ghosts". At this point they added green and purple ghost marshmallows. The green marshmallows were based on Slimer. His picture was even added on the front."
- https://ghostbusters.fandom.com/wiki/Ghostbusters_Cereal