The chaotic and indecipherable online community known as /b/ has bestowed upon us a fresh Internet horror: They call it the “bikini bridge,” and some disreputable Web sites have already christened it the latest beauty craze.

Here’s some quick background, for those of you uninitiated in the ways of 4chan. 4chan is a profoundly popular, largely anonymous message board that specializes in memes and mischief. /b/ is a 4chan forum best known for its penchant to sow stupid, occasionally dangerous, ideas across the wider Internet. The problem is that these “pranks,” as many so casually term them, can often acquire lives of their own — becoming actual trends even as we dismiss them as hoaxes.

Such is the case of “bikini bridge,” it seems — and such is the fickle nature of truth and fiction online. Per The Daily Dot, this week’s rush of interest in the bridge (a term for protruding hipbones that has existed, if quietly, since 2009) stems from a 4chan plot to popularize it. The plot was pretty simple: circulate bikini bridge images on social media, and then create a fake bikini bridge backlash. Watch the “controversy” explode. Sit back and read the media coverage. Laugh, presumably.

The media has indeed reported the story — as a hoax or a prank, in many cases. “Don’t fall for the ‘bikini bridge’ prank the Internet is playing on you,” teases the headline on Today.com.

But writing this off as the invention of a weird Internet niche — nevermind, no worries, nothing to see here — totally misunderstands the information ecosystem. Online (and to a less immediate degree, in “real life”), attention and clicks and tweets all beget more of the same. Maybe the “bikini bridge” wasn’t a trend when 4chan started talking about it, but it is now. The photos are cycling through “thinspo” hashtags and pro-eating disorder blogs. They’ve come to the attention of the the National Eating Disorder Association, an organization that advocates for healthy self-image.

“People with poor body image who are at risk or actively struggling with disordered eating tend to fixate on particular body parts; there is nothing new about those obsessions,” said NEDA’s Claire Mysko in an e-mail. “What is new is that coined terms like ‘thigh gap’ and ‘bikini bridge’ — and the news articles, images, hashtags and social media comparisons that come with them — have given those obsessions larger and more competitive platforms.”

Note that it doesn’t matter in the slightest where the images and hashtags started, or if the fad began as “real” or “fake.” The difference between the two is malleable online. And the agitators of /b/ understand that better than anyone, which is perhaps the very purpose of so-called pranks like this one and last year’s #cuttingforbieber, in which the forum convinced many outlets that Justin Bieber fans were literally self-mutilating out of love for him. (Appallingly, an indeterminable number of fans may have actually followed suit.)

The bikini bridge is, in some ways, less destructive — there is, as Mysko points out, nothing at all novel about this type of unhealthy and unrealistic image, which fans brand “thinspiration.” But the genre as a whole is still dangerous, NEDA warns, and its origins don’t make it any less worrisome. If anything, 4chan’s effortless orchestration of a dangerous trend should worry observers more.

“This should cause large enough of a stir to snowball into a fairly big subject,” reads the 4chan post that started it all. “Target NYers, weight loss pages/groups (as a “goal”), etc. These people already hold a predisposition.”

“Even just mentioning ‘bikini bridge’ … will create a buzz.”