According to the
Ghostbusters,
Zuul was a demigod worshipped by the Hittites, Mesopotamians and the Sumerians.
Zuul was the minion of
Gozer.
At first
Zuul posessed a statue on the roof of a building, and later it posessed the body of
Sigourney Weaver, which was a much better choice.
"There is no Dana, there is only
Zuul."