Containment Unit
From Multiversal Omnipedia
The Containment Unit was a large machine developed by the Ghostbusters which could imprison large numbers of ghosts and similar ectoplasmic entities. The original unit was destroyed due to the interference of Walter Peck, prompting Egon to rebuild it as a much larger, more secure machine.
Real Ghostbusters
The interior of the unit was a pocket dimension, filled only with floating rocks in a void.
The Peoplebusters of Boo York had their own containment unit, resembling a large skull. Its interior resembled an idyllic, grassy plain.
