The "flash-box" was a device that generated an invisible barrier around the town of Chester's Mill, Maine. The device appeared on Black Ridge on October 21, 2012. Along with generating the Dome, it emitted a band of ersatz radiation that drove animals to suicide, caused visions in humans who passed through it, and glowed at night.
The box was found on the 24th of October by Joe McClatchey, Benny Drake, and Norrie Calvert using a Geiger counter, and was later examined by Rusty Everett on the 25th of October. Upon touching the device, Everett experienced a vision of the beings that created the box, as well as reliving a terrible memory from his childhood. He could not, however, move the device or turn it off.
On the evening of the 26th of October, several more citizens fled to Black Ridge, where they also touched the device. Each person saw the beings – which they referred to as "leatherheads" – and relived their worst memories. On the morning of the 28th of October, Sam Verdreaux, Dale Barbara, Julia Shumway returned to the box, and Shumway successfully pleaded with the beings telepathically to release them.