It would appear that the Western media have, yet again, conjured up a “Big in Japan” trend.

If “bagel head” means nothing to you, here’s a recap: “Taboo,” a show on National Geographic, ran a segment earlier this week on a kind of extreme body modification that has been happening in Japan’s underground for years. It involves injecting saline into the forehead and then sometimes putting a depression into the bulge in a way that comes out looking like a bagel or a doughnut.

Predictably, U.S. media outlets such as the Huffington Post, CNN and Mashable, and the U.K.’s The Sun and Daily Mail quickly turned out attention-grabbing stories that insinuated that this was the latest Japanese trend. “Japan’s hot new beauty trend?” asks the HuffPo headline, for example.

People outside of Japan seem to be taking the “news” at face value. A tweet from @OMGFact about the “Japanese trend” has been retweeted hundreds of times.

Most observers in Japan, however, know better. @SublightMonster tweeted “Bagel heads: hot new trend, or yet another lazy journalist turning in yet another ‘wacky Japan’ piece?” @Mulboyne, a British Twitter user based in Tokyo, wrote that he was surprised to run into some bulging foreheads at an underground party in 2009. He told us the hardcore body-modification fans there simply called it “seerin durippu” — saline drip. “One reaction was ‘Kimochi warui!‘ (gross!). It looked a bit unsafe,” he said. “There was a lot of amusement, too, of course.”

To set the record straight, we spoke with La Carmina, a well-known subculture blogger and TV host. Her team, La Carmina and the Pirates, actually did the legwork for National Geographic. They hooked the producers up with Kerropy Maeda, the man who brought this type of saline injection to Japan in 2007 after seeing it in Canada. La Carmina and her crew even supplied the show with its models. (To learn more about Maeda and the Tokyo scene, read this excellent interview in Vice published last year.)

Nevertheless, La Carmina takes issue with how it ended up being exaggerated, not on National Geographic, but on the coverage that followed. “It is not a trend even among the most hardcore body modification types,” she said. “It’s expensive. It takes specialized equipment. Most Japanese people don’t even know about it.”

Indeed, some Japanese media are hearing about it for the first time.

A reporter for Excite News wrote: “Having never heard of ‘bagel head’ I was as surprised as anyone to see these pictures of young people. A perfectly cute forehead transformed by a grotesque swelling. It looks quite like a space alien. I shudder to think, but according to news sites all over, this is Japan’s latest trend?”

La Carmina said she had been blogging about bagel heads (and other, arguably more extreme, forms of body modification) for years. “There’s a strong, supportive subculture in Japan who are into trying new things. It’s just another method of expression, like piercings or tattoos, but it is certainly not a trend,” she said, adding for clarification: “It is absolutely not permanent. It lasts for a night and then you pee it out.”

Her friend John, who got his bagel done for the National Geographic show, thought it would be great if all this attention led to a greater understanding of underground cultures. Sadly, though, as he points out, “if you say something on the Internet about Japan, people tend to believe it.”

Naturally this isn’t the first time. Remember the last wacky “new Japanese fashion,” the LED mouthpieces reported on by the New York Times Bits Blog? That story was amended when it turned out to be born out of an ad campaign.

Think we’ll see corrections for this wave of stories, too?

[Postscript: We’re now a footnote in the meme.]