21. Egon, Uh, Finds A Way
As the brains of the outfit, the Spengler character needed to be played by someone who could convincingly portray a bit of a boffin, and so the search was on for the right kind of actor to fill the rather sizeable shoes of such a character.
Original choices included Christopher Walken, John Lithgow, Christopher Lloyd and Jeff Goldblum – all interesting names on paper, but none were quite right when it came to the crunch.
In the end, Ramis decided to resurrect his own dormant acting career and assume the role himself, which made perfect sense and he'd spent so much time crafting the character in the writing process, even drawing inspiration for the character’s name from his classmate Egon Donsbach.