The Babylonian Slave Ship run by a Slave Driver and manned by Slaves was used by Prime Evil to travel to Babylon after he forced the Time Gyroscope to turn the clock back 5000 years. Why Prime Evil would take such a slow route is not completely clear, except for the fact that he was under the impression that he had finally defeated the Ghostbusters as they, like all people from 1986 would have been regressed back into nothingness thanks to time turning back.