A sphinx is turning Manhattan's intellectuals into blathering idiots as punishment for not solving his riddle. Meanwhile, Egon is depressed over getting old and starts to impose himself in the Ghostbusters' field work.
- Egon Spengler - Maurice LaMarche
- Janine Melnitz - Pat Musick
- Kylie Griffin - Tara Charendoff
- Eduardo Rivera - Rino Romano
- Roland Jackson - Alfonso Ribeiro
- Garrett Miller - Jason Marsden
- Slimer - Billy West