Etsy shop VikingProps has this highly detailed Proton Backpack Prop for sale, based on those seen in the Ghostbusters movies. It’s constructed from unspecified metal, wood, and plastic with weathered paint and decals and is true to scale. What really caught my eye, however, is that it’s built using an A.L.I.C.E. pack frame. As the video below shows, the Proton Pack can also be upgraded with full lights and sounds, making it quite possibly the ultimate Ghostbusters Cosplay accessory.