A disc in the post
Some time around June 2015, an envelope postmarked Warsaw arrived at a post office box in Helsingborg, Sweden. It carried no return address and was addressed to "Johny K." — John-Erik Krahbichler, the founding editor of a small tech blog called GadgetZZ. Inside was a DVD. Written on the disc was a string of base64, and the plaintext it decoded to became the name the thing has carried ever since: 11B-X-1371.
Krahbichler sat on it for months. On 12 October 2015 he posted about it, describing a creepy puzzle that had turned up in his mail. Within a week it was in Gizmodo, The Washington Post, Slate, the International Business Times and the Daily Dot, and the people pulling it apart had found enough inside it to make it look, for about a fortnight, like evidence of a crime or notice of one.
What is on it
The video runs two minutes. It is black and white. A figure stands in a derelict room in a long hooded cloak and a beaked leather mask of the kind associated with plague doctors, holding a blinking light in one palm, moving very little. There are no credits and no sound a viewer would call sound.
The content is underneath. Run the audio through a spectrogram and images appear in the frequency plot, along with the plaintext "You Are Already Dead". A pattern of triangles and squares resolves in the Pigpen cipher to the Latin Ad oppugnare homines — to attack men. A passage of morse code reads "RED LIPS LIKE TENTH". Twenty pairs of two-digit numbers, read as coordinates, give the latitude and longitude of the White House. One decoded line refers to an eagle whose disease will spread, which readers took for a threat of biological attack, and the number 1371 was read against the Black Death, which is also where the mask comes from.
Later readers noticed that "RED LIPS" is an anagram of a phrase about killing a president. Krahbichler himself decoded a reference to a "BLACKBEAST", which he took to mean Barack Obama, and concluded the thing was political rather than terrorist.
The part that looked worst
The images hidden in the spectrogram were of mutilated and tortured women, and for a short period the obvious reading was that the sender was documenting his own murders.
That reading did not survive being checked. Researchers traced the stills to their origins: one to the 2010 film The Bunny Game, one to a 2007 German film called Slasher, and one to a crime-scene photograph of a victim of the Boston Strangler. The pictures were found material. Whatever the video is, it is not a record of anything its maker did to anybody.
Reporting has not established that any police force opened a case. Public interest ran well ahead of official interest, and the two never met.
The building
A Polish reader identified the location: the former Zofiówka Sanatorium near Otwock, south of Warsaw, a ruined Jewish tuberculosis sanatorium with a grim history of its own. The identification was made on the window openings and on graffiti visible in the video, and the graffiti gave a rough date — it is absent from a photograph of the same room taken in November 2013.
Earlier copies
The October coverage had the sequence wrong. The video had already been posted to YouTube in May 2015 by a user called AETBX, with a title and description written in binary; decoded, the title read "Muerte" and the description a line of Spanish meaning that the reader had one year less. It had also appeared on 4chan's paranormal board.
AETBX denied making it. He told the Daily Dot that anyone can fake a DVD, and he told The Washington Post that he had received a copy in the post himself, identifying himself only as Daniel, from Spain. A student film group's website at the University of California, San Diego was hacked and a frame from the video posted on it, which looked briefly significant and turned out to be one of many unrelated images the intruder had left.
Who says he made it
In late November 2015 a Twitter account appeared in the name Parker Warner Wright and began hinting at authorship. In an interview with Mike Wehner of the Daily Dot published in January 2016, Wright said he was an American citizen living in Poland and that the video was an art project — the first of a series.
His account of distribution was specific: he made three copies in May 2015, left two of the discs in a Polish subway station and a park, and posted the third to 4chan. He said he had chosen Krahbichler more or less at random — that the blogger had won what he called the business card lottery. Asked for proof, he set a test that only the maker could pass and invited people to reproduce his mask exactly. Krahbichler accepted the claim in January 2016.
A sequel followed on 1 January 2016, announced in advance for a time given as exactly 1.444 metric hours: 11B-3-1369, with the description "Their lies unlock our dissent" and a woman in a white dress with a bandaged face. Another, 110A30213, went up in November 2016, which Krahbichler described as very political.
A separate man named Parker Wright, unconnected to any of it, had to deny being the uploader.
The theories that were not the answer
Before the authorship claim, the commonest explanations were marketing. The video was read as a campaign for the film Inferno, for Syfy's 12 Monkeys, for a Polish games studio, and for a Skrillex track called "Red Lips" — the musician had used the hashtag, which was the whole of the evidence. None of them was ever substantiated, and the plague-doctor mask and a plague-year number were enough on their own to generate the first three without any company's involvement.
Where it stands
The puzzle has a claimed author who gave an interview, described his distribution method, and set a verification test. That is more resolution than most internet mysteries get, and it still rests on his word plus a mask nobody else managed to duplicate.
It is also not finished. On 18 March 2026, GadgetZZ reported a new puzzle sent from Otwock — the same town as the sanatorium — on a DVD holding six binary files. Those were partly solved, and led to a Tor hidden service that did not answer.
What the case actually illustrates is how a short video becomes a threat. Every alarming element in it was real: the Latin, the coordinates, the morse, the corpses in the spectrogram. Each one, traced, turned out to point somewhere other than a crime — to a horror film, to a decades-old police photograph, to a landmark anyone can find on a map. The menace was entirely in the assembly.