For 25 seconds in 1987, in the middle of WGN-TV anchor Dan Roan’s sportscast, thousands of Chicagoans’ feeds were replaced with a low analog whine and the eery image of a masked man nodding over and over as if in a state of mania. “If you’re wondering what’s happened, so am I,” Roan said to his audience once WGN regained control of the signal. What he couldn’t have known is that the rest of the world would still be wondering to this day.