IDW Publishing Comics- Ghostbusters Volume 9 (also known as Ghostbusters- Mass Hysteria! Part 2) is a trade paperback collection published on December 10, 2014. It features a cover that connects with the cover of Volume 8 to form one image, a forward by Jennifer Runyon, covers spread throughout the trade, variant cover art gallery, and a 30th Anniversary advertisement for previous volume trade paperbacks and omnibus editions of Ghostbusters Omnibus Volume 1, The Real Ghostbusters Omnibus Volume 1, and The Real Ghostbusters Omnibus Volume 2. This trade paperback collects: