Fans and journalists have almost universally adopted the name “DC Extended Universe” for the series of interconnected comic book movies produced by the studio, but that was name that began as a joke.

According to Vulture’s Abraham Riesman, who authored a deeply reported look at the current state of DC Entertainment, the name is not used within the company or in any official capacity at all. Officials within the company told Riesman they didn’t even know where the name came from.

Riesman explained on Twitter that he traced the phrase back to a 2015 Entertainment Weekly article by senior editor Keith Staskiewicz.

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“This isn’t just a single movie, it’s a waystation to the upcoming ‘Justice League’ double-fister, not to mention a whole slew of other attractions on the DC Extended Universe™ road map,” Staskiewicz wrote in an article about the then-upcoming “Batman v Superman: Dawn of Justice.”

“The writer of the article, Keith Staskiewicz, was hard to track down. Not on Twitter. No website,” Riesman wrote in a series of tweets. “Finally got him on Facebook and asked about the term. Turns out he just straight-up made it up as a joke.”

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Staskiewicz explained to Riesman that the capitalization and trademark symbol he used in the piece, which all went toward making the moniker seem more official, were “sardonic” additions to a throwaway joke in the middle of the article. “Just seemed like the kind of thing they’d call it!” he said.

“Years later, it’s in use everywhere as though it’s official,” Riesman wrote. “The lesson: never make a joke, because no one gets jokes.”

THREAD: I have a fun thing I learned about the term “DC Extended Universe” while reporting this story: https://t.co/c2wkmXxNLH — Abraham Riesman (@abrahamjoseph) September 29, 2017

Early on in my reporting, officials at WB/DC told me no one uses the term “DC Extended Universe” internally and that it’s not official — Abraham Riesman (@abrahamjoseph) September 29, 2017

I did some digging and found the first usage: this EW article from July 1 2015 https://t.co/EyAiHfRNQE pic.twitter.com/unxdJk0Sgj — Abraham Riesman (@abrahamjoseph) September 29, 2017

Finally got him on Facebook and asked about the term. Turns out he just straight-up made it up as a joke — Abraham Riesman (@abrahamjoseph) September 29, 2017

Per him: “I just looked back on the piece now and noticed the (in-my-mind) sardonic little trademark symbol I gave it. Whoops.” — Abraham Riesman (@abrahamjoseph) September 29, 2017

Years later, it’s in use everywhere as though it’s official. The lesson: never make a joke, because no one gets jokes — Abraham Riesman (@abrahamjoseph) September 29, 2017