Hacking into the Home Depot credit card system, the financial records at JP Morgan Chase? Child's play! Try hacking into the feed of a local Chicago television station and replacing the sport anchor with a really creepy incarnation of Max Headroom.

Around 9 o'clock on November 22, 1989, Chicago residents witnessed this epic hack. The evening news sportscast cut out, and a person in a strange mask appeared, dancing around in front of a spinning piece of metal—a rather dark incarnation of Max Headroom, the rather inexplicable character at the heart of the British TV series Max Headroom: 20 Minutes into The Future and two subsequent TV shows. On these shows, Headroom had a tendency to interrupt the broadcasts of the fictional TV station Network 23, but this wasn't an authorized appearance by the character. It was a real pirate transmission.

After about 30 seconds, WGN's technicians were able to override the pirate signal. "Well, if you're wondering what's happened, so am I," the station's sports anchor Dan Roan said when the signal was restored. But two hours later, PBS affiliate station WTTW's broadcast of Doctor Who was similarly interrupted. This time, the pranksters were able to broadcast their entire video, complete with audio. And what nightmarish audio it was. "Yeah, I think I'm better than Chuck Swirsky!" the infiltrator announced in a high pitched, distorted voice, referring to the Chicago area sports announcer.

>'Well, if you're wondering what's happened, so am I.'

It's been nearly 27 years, but the incident remains a mystery. The perpetrators were never caught. Like most of today's acts of cyber-vandalism, the content of Max Headroom interruption was juvenile. But also like today's hacks, the prank required sophisticated technical skills. "Exactly how these pirates were able to pull off the overriding of WGN-TV and WTTW-TV's signals is not yet known for certain," Chicago Radio and Media reported in 2012.

The prevailing theory is that the hijackers beamed their own signal from a tall building, or perhaps a van, directly at WGN and WTTW's antenna, overpowering the signal sent by the companies' own transmitters. At the time, WGN officials speculated that the pranksters would have needed powerful, expensive equipment to override its broadcast. But last year, the FCC's lead investigator of the incident, Michael Marcus, told Vice Motherboard surplus amateur radio gear would have done the trick, though it would have at least required significant knowledge of broadcasting technology.

Perhaps the perpetrators were broadcasting students from a near by college. Or maybe they were disgruntled WGN employees. Although the longer broadcast was on WTTW, it appears that WGN was the real target since the perpetrators made WGN-related references, including the mention of Swirsky and humming the theme of the cartoon Clutch Cargo.

Whoever they were, they made a lasting impression. "I just made a great masterpiece for all the great world newspaper nerds," their Max Headroom said, making another WGN reference (WGN stands for World's Greatest Newspaper). Surely, they knew their prank would make the local papers, but it's doubtful they realized that we'd still be watching their video decades later.