Species: terror dog
Terror Dogs are a vicious breed of demonic hellhounds found in the Ghostbusters franchise dating back to the original film.
Terror Dogs are large and bulky monsters vaguely resembling actual dogs but have horns and glowing red eyes as well as a degree of intelligence and can possess human beings as vessels. Although rarely seen, there seems to be more than one type of Terror Dog, with a much larger breed being briefly seen in the cartoon series.
The most famous (as well as the most powerful) Terror Dogs in Ghostbusters canon were the two loyal servants of Gozer known as Zuul and Vinz Clortho.