Zunk is a child-like entity in a trio of ghosts. They appear to originate from New Jersey, according to the P.K.E. Meter readings taken while they haunted a Conrad's chocolate plant.
The Ghostbusters eventually captured them after a lengthy bust, but they escaped from the Containment Unit. Slug desired revenge and set up a fake paranormal eliminations and investigation business to bankrupt the Ghostbusters. Zunk would act as the ghost haunting a location then his parents would arrive and pretend to capture him.