Olbia in Hayasdan? That would be the only really plausible thing in your post. Yes, screens or it didn't happen.

The strangest expansion I've seen would be the Beige Death, courtesy of the Sauros. I'm not sure what triggered it (But I was Pahlav, and cut off their North, so that probably had something to do with it) and they just sweeped through the AS by hiring all the mercs before the Seleucids could.