Marvel’s Loki episode 5 has a really unique Easter egg showcasing a video game that barely even existed, yet whose reputation has grown thanks to the power of urban legend. Visible in the secret hideout of the Variant Lokis, nestled between some old pinball machines and stacks of ephemera, is an arcade cabinet bearing the name: Polybius. It’s not exactly out of place on a show that relishes in jumping around the timestream and into and out of troublesome branch realities. The show has hidden little jokes all around the TVA offices indicating that representatives of the time-and-space-spanning organization like to drink and snack on long defunct brands. Why shouldn’t they? If you could get a bottle of Josta and all it’s going to take is a jaunt back to 1997, why not, right? But Polybius takes things a little further. Loki could have just as easily gone for a Crystal Castles or Mad Crasher or Zaxxon cabinet if all they wanted was some fun and anachronistic set dressing. But the presence of Polybius is something a little more mischievous, a little more deceptive, and thus a little more perfect for this show. Before Qanon, Slenderman, and deep-fake news confusions evoked international viral fears, concerned citizens worried about the brain-flaying properties of video games. Today, the American Psychiatric Association is studying “Internet Gaming Disorder” to determine whether it can be classified for potential diagnosis in an age of easy technological access. In the 1980s, kids had to go to video arcades to pump quarters into machines which mined their minds. According to urban legend, Polybius, an arcade game, was specifically designed to encroach on the players’ psyche. The legend says it was tested on civilian youth at the Malibu Grand Prix arcade in Oregon between 1979 and 1981. Players reputedly complained about nausea, headaches, blackouts, amnesia, night terrors, seizures, and even brain aneurysms. Some had auditory hallucinations, while others saw faces out of the corners of their eyes. The most extreme hazard of playing Polybius was to swear off video games forever. The earliest written account of the game is an archived Usenet post from 1994, according to PCGames. The Polybius legend grew after a Feb. 6, 2000, listing in the digital arcade gaming database CoinOp.org. According to the post, the “game had a very limited release, one or two backwater arcades in a suburb of Portland. The history of this game is cloudy, there were all kinds of strange stories about how kids who played it got amnesia afterwards, couldn’t remember their name or where they lived, etc.” Admittedly, this happened in the ‘80s, when an actor played a president while the vice president was a former CIA director. Some conspiracy theorists posit Polybius was a brainwashing device designed by the agency, a concern raised in the original post. “The bizarre rumors about this game are that it was supposedly developed by some kind of weird military tech offshoot group, used some kind of proprietary behavior modification algorithms developed for the CIA or something, kids who played it woke up at night screaming, having horrible nightmares,” the CoinOp listing reads. MK is said to stand for Mind Control, although conspiracy theorists suggest it can stand for Mein Kampf. Much of the secret project’s research was done under the supervision of Nazi scientists who had been brought into the country under Operation Paperclip. The listing says Polybius was manufactured by a company called Sinneslöschen, which means delete, or more vaguely, sensory deprivation. But the plot of the listing twists further. There are indications someone was monitoring the players. “According to an operator who ran an arcade with one of these games, guys in black coats would come to collect ‘records’ from the machines,” the posting reads. “They’re not interested in quarters or anything, they just collected information about how the game was played.” The suggestion that Polybius tested mental and physical agility, and was being used as a recruitment tool for the military is almost canon now. The idea that video games have been used to militarize youth has been the subject of books, comics, movies, and episodes of The Simpsons. There are probably video games about it. The name comes from the ancient Greek historian and cryptographer Polybius, who emphasized the importance of quoting eye witnesses for noteworthy events. Since the legend began, many people have claimed to have played the game, and some have said they own a ROM version of it. None of these have been corroborated and no physical evidence exists. Steven Roach came forward in 2006 to claim he was one of the game’s programmers, according to PCGames. He explained it was pulled from the arcades after someone suffered an epileptic seizure during play. Roach’s claim has been widely written off as an internet prank, but a theory claiming Polybius was an early code for the game Tempest persists. Early testing of that game also noted epileptic seizures in players. A similar theory suggests that the “real” Polybius is actually a somewhat obscure 1983 arcade game called Cube Quest. Not only does Cube Quest feature some of Polybius‘ (and Tempest‘s) most notable gameplay and visual design elements, but its advanced technology reportedly caused Cube Quest machines to break down more frequently than other arcade cabinets of that era. That would certainly help explain why people vaguely remember a trippy arcade game that was constantly being serviced by strange figures who always seemed to be around it.