Zuul
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, manifesting her possession in Dana by making her more sexually aggressive and also giving her the ability to levitate and growl monstruously like a beast. After being successfully located by and mating with Vinz Clortho, the buidling's other possessed tenant, Zuul opened the interdimensional portal for Gozer and transformed back to her natural Terror Dog form once Gozer is free, trapping Dana inside of her demonic being. Zuul is 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.
