It's the Stay Puft Marshmallow Snowman

Gozer: "The choice is made!"

Peter: "Whoa! Ho! Ho! Whoa-oa!" (or something like that.)

Gozer: "The Traveller has come!" 

Peter: "Nobody choose anything!" 

Peter asks Egon, "Did you choose anything?"

Egon: "No."

Peter asks Winston, "Did you?"

Winston: "My mind is totally blank." 

Peter: "I didn't choose anything!" 

They all look at Ray who backs away with guilt. 

Ray: "I couldn't help it. It just popped in there."

Peter: "What? What just popped in there?"

Ray: "I tried to think--"

Egon: "Look!" 

Ray: "No! It can't be!" 

Peter: "What is it?" 

Ray: "It can't be!" 

Peter: "What did you do, Ray?"

Winston: "Oh, shit." 

They see what's coming and it's this ... 

I wonder if Peter would still use the sailor trying to get laid line if Stay Puft was a snowman. 

(Oh and the sad part is, the whole transcript is from my memory of watching Ghostbusters countless times. I only went online to verify I was right. I'd give myself about a 90/100.)