Unstable Ghosts are hundreds of ghosts who entered the physical plane by artificial means thanks to Mr. Tummell.
Mr. Tummell refused to give up his possessions after he died and had technology built so that he could transmit it all to the Netherworld. He opened a direct passage but the door swung both ways. Hundreds of ghosts appeared. However, due to the nature of the technology, the ghosts' ecto-molecular intro-structure was rendered unstable. They would break up and each fragment would become a new ghost. In 15 hours, the planet would be completely overrun.   The Ghostbusters overloaded Tummell's equipment with their own and caused the ghosts to be pulled back into the Netherworld.
- ↑ Egon Spengler (2009).The Real Ghostbusters- "You Can't Take it With You" (1986) (DVD ts. 09:21-09:23). Time Life Entertainment. Egon says: "And their ecto molecular intro-structure is unstable."
- ↑ Egon Spengler (2009).The Real Ghostbusters- "You Can't Take it With You" (1986) (DVD ts. 09:28-09:30). Time Life Entertainment. Egon says: "Unfortunately, each new fragment will become a complete ghost."