The costumes are called “zentai” – taken from the Japanese words zenshin taitsu, which roughly translates as “full body tights.” A small subset of Japan’s cutting-edge and determined trendy outsiders are zipping themselves into the zentai (or morph) suits and, say, hitting happy hour while clad in head-to-toe spandex. The people brave enough to wear the suits are hard to miss when they step foot in public, but the mask renders the wearer completely anonymous. It’s that juxtaposition of brazen anonymity that makes zentai alluring.

Dialectically speaking, “zentai” tends to be more fetishistic, while “morphsuits” are for more mainstream cosplay fun and are likely to show up at football games, ComicCon, or frat parties. Whether you prefer the name zentai or morph, the suits generally look the same: They envelop the entire body, including the hands, feet, and head. They can be completely blank black, white, or primary colors or decorated with the costume of a superhero or in a dizzying array of patterns from optical illusions to leopard print, camouflage, and newsprint (a good present for an editor, no?). There are zentai ninjas, zentai Pokemon, the flags of many lands, and an inordinate number of Spiderman zentai. With so many costumes to choose from, it’s no surprise that “zentai addict” and “zentai fetish” show up on Facebook.

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While there certainly can be a sexual fetish associated with zentai (one that manages to be overtly sexual, yet not at all revealing, as everyone is covered in head-to-toe spandex akin to the full body condoms that Woody Allen envisioned in Sleeper), one member of Tokyo’s Zentai Club offered the BBC a far more wholesome explanation for the trend: “I was always fascinated by hero costumes as a child.” For some, wearing the costume comes complete with a superhero mission — one zentai fan gained some notoriety in Japan for standing guard in his costume at a subway station just to help women carry their baby strollers down the stairs. For others, though, donning zentai can create a sense of liberation in an otherwise repressive culture.

Ikuo Daibo, a professor of psychology and human behavior at Tokyo Mirai University, sees the zentai subculture as a way for people to express their “deeper selves” in an anonymous fashion. “In Japan, many people feel lost; they feel unable to find their role in society,” Daibo told AFP. “In a way, they are trying to expose their deeper self by hiding their own identity,” said Daibo.

“I have led my life always worrying about what other people think of me,” agreed Hokkyoku Nigo, a zentai enthusiast who also spoke to AFP. “I always felt suffocated by that. But wearing this, I am just a person in a full body suit.” As Jean Cocteau said, style is a simple way of saying complicated things.

While the quiet trend may have started in Japan in the ‘80s, although popularity has resurged lately, it has spread far beyond the shores of the island nation. A Chicago couple starred in a National Geographic documentary about zentai. The Zentai Project group, which is based in Britain, says its members wear the suits “for the amusement of themselves and the public.” YouTube is filled with videos showing zentai enthusiasts around the globe, including Russia, Germany, Thailand, and Brazil — a sign of the global community of zentai wearers who swap videos, organize meetups, and gather on forums and blogs to discuss their intricacies of their lifestyle.

While zentai is a subculture — and will certainly never reach the mainstream — it does have almost 11,000 likes on Facebook as an “interest,” and online retailer Morphsuits U.K. has close to 1.5 million Facebook fans.

So how much do anonymity and community sell for? Around $40. The price creeps up to $75 for a Spiderman suit complete with 3-D raised spiders on the back or for something called “A Slender Man” morph suit, which costs $64.95, but is dinner-party ready (aside from the fact that you can’t eat while wearing it) with a printed-on suit jacket and tie.

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While the cost is manageable for the occasional bodysuit fan, it can add up quickly for a true fan of zentai. ShinyBlue, which is the preferred pseudonym of one of the moderators of the Ayus-Zentai forum and fan site that has over 1,500 members, has spent more than $2,000 on lycra and spandex suits over the years.

ShinyBlue got interested in zentai back in 2005, purchasing his first suit soon after. The most he’s ever spent on a single suit is $200, which he purchased from a high-end manufacturer called Fets-Fash. Prices on the site range from 69.95 euros for a blue cat suit in a polyamide blend to over 200 euros for a gold cat suit with transparent eyes, covered hands and feet, and double zippers.

For the true aficionado, though, the extra cost is worth the improved quality. “What I look for quality-wise in a zentai is a good fit,” said ShinyBlue, noting that it can be very troublesome to get a well-fitting zentai. “I look for a smooth and stretchy fabric blend, strong durable stitching, and finally a good pattern,” he told Fortune via email. “There are actually many ways to sew up a spandex body suit, and I’m always on the lookout for a good sewing pattern such as ones with roomier toes, ones that avoid having stitching along the outward side of the legs, no seams on your face, etc.” When you spend your free time (or 28 days straight like one British woman) clad in spandex, comfort is key.

Back in 2011, David Hibler, the inventor of Forever Lazy — a line of fleece one-piece footless adult pajamas — told CNNMoney that when it came to his product, “We were selling laziness.” Purveyors of zentai, though, are selling something else entirely: a mode of expression, a means for anonymity, and a community.

One thing we know for certain, though: It is not even close to being Japan’s weirdest trend.