The Gas ghost is an entity captured in an undisclosed bust by either the original Ghostbusters or the Extreme Ghostbusters. In 1997, it was one of two ghosts that escaped while Roland Jackson was trying to free the Banshee. It flies and breathes smoke. Its breath, combined with the fiery breath of the Donkey ghost can cause an explosion. The gas ghost was recaptured by Egon Spengler. While Egon re-secured the containment grid, the others went after Roland and the Glostic Sisters.