Zuul

From Multiversal Omnipedia

Zuul, a ferocious female Terror Dog, was the Gatekeeper of Gozer. Being female, she had shorter horns than her male counterpart, Vinz the Keymaster. She was worshipped in 6000 BC by various primitive civilizations, and, along with Vinz, had a gargoyle crafted in her likeness flanking the temple on the roof of the Shandor Building.

After "hatching" from their statues in modern times, the two Terror Dogs possessed two tenants in the building in order to copulate and thus open the gateway to Gozer's dimension. Zuul chose to possess Dana Barrett. She returned to her natural form once Gozer was free, trapping Dana inside her being, and was then destroyed when the Ghostbusters "crossed the streams" and reversed the particle flow through the gateway, creating a massive explosion. Dana was extracted, alive and unharmed, from Zuul's burnt corpse.