I entered the pool area of the DoubleTree by Hilton Hotel Seattle Airport just in time to see a man dressed as Gomez Addams bend down on one knee and propose to a woman with rippling red hair and a green mermaid dress.

When she happily accepted, giddy applause burst from the other hotel guests gathered around the pool. That's when I noticed that they all had tails instead of legs.

"I would kill for her! I would die for her! Either way, what bliss!" bellowed Gomez, and around him a pod of mermaids splashed down from the poolside into the chlorinated water, undulating in celebration.

I was at the DoubleTree for Norwescon, a science-fiction and fantasy convention, and I'd just stumbled upon a daylong gathering for mermaids of the Pacific Northwest.

"We have a lot of merfolk from Portland to British Columbia," said Triton Mahtlinnie, who was sporting a purple tail.

"Sometimes we go on adventures," said Sif, who flapped the yellow tail she was wearing. Next to her was the wheelchair she was using to get around the hotel, a not-uncommon mode of transit for mers on land. "We'll swim around in a creek or do a dive-in movie." That's when they project a movie on the wall of an indoor pool. When the weather is nice, they'll descend on sites known to attract mers, like Portland's Keller Fountain Park, where there is an arrangement of shallow pools and waterfalls.

As I gazed around the pool, I thought of course Seattle has a robust merfolk community. How could we not? The Pacific Northwest has communities for pup role-players, for leather contests, and for amateur burlesque. And Seattle is one of the most furry-friendly climates I've ever experienced. Furries are people who slip happily into an identity as an anthropomorphic animal. They express themselves in a variety of ways, from online role-play to art to paw-print socks to elaborate fur suits. Like mers, the furry fandom bids a giddy "no thank you" to the constraints of our species, an outward expression of an inner character that feels truer than the bodies they're born in.

But of all the outfits and identities and mythical creatures, why this? The idea of plunging into water with my legs bound together strikes me as terrifying—what is it about mermaids that has the power to seduce? Who are these people?

The ones I spoke to described a lifelong desire to live amid the waves, hearing a call from the water like sailors lured by mythical sirens. The only difference is that these people are willingly entangled and absorbed into the mythology, rather than struggling to an all-too-human death on rocky shores.

On any given weekend, the mermaids might meet up in full regalia to splash in a cove or an indoor pool, they might slip into human clothes to craft tails and costumes, they might make the most of some solitude by drawing mermaid art, or they might channel their interest into a side business or educational enterprise. Water is the common thread, whether that means lounging calmly as waves lap at a bank or tumbling in a soothing current. To be a mer means immersing yourself in a peaceful flow, both physically and mentally.

"A good chunk of what I do is performance," said Essie, who dresses in complex costumes and entertains crowds at parties, libraries, and corporate events. She's also getting a master's degree in environmental policy.

"Even back in middle school, I was volunteering with conservation groups," she said. "Mermaiding has allowed me to reach a wider audience and encourage conservation through imagination."

As communities go, mers tend to have a low profile, which can make them difficult to locate. Participants often describe discovering their tribe by accident. Essie said, "I always enjoyed swimming, but I never thought about being a mermaid until I went to a Filipino mermaid academy."

She was visiting family in the Philippines and saw an article about a facility that lets visitors rent a tail and swim among the fish. She expected the experience to be fun—not life changing. (No word on what the fish thought of these aquatic exchange students.)

"It was one of the greatest experiences of my life," she said. "I ran out of there and I told my family, 'This is what I'm going to be.' They laughed and said, 'Sure, of course you'll be a mermaid.'" A couple of years later, Essie has a part-time business in Seattle doing underwater photography and portraiture, and she offers "Mermaid for a Day" packages for people who seek the same experience that meant so much to her. Once she has her customers floating in a pool with a tail on, she finds the conversation naturally drifts toward the environmental subjects in which she's pursuing her degree.

"It's been a way to talk to adults," she said. "There are people who've never wanted a tail before, but want cool pictures, and it's a gateway to talk about conservation and environmental policy in general."

It's difficult not to want to exchange at least a few words when you come upon someone in a mermaid tail. Like any expression of one's hidden depths, the costume begins a conversation. The tails, seashell bras, and seaweed tiaras are familiar pop-cultural icons. You might not know exactly what mermaids stand for, but you at least recognize the accoutrements, in the same way you can draw conclusions based on a person's band T-shirt, or collection of Pokémon, or the contents of their DVR.

"A lot of people were inspired as kids by movies like The Little Mermaid or Splash," said Triton, whose preferred pronoun is they/their. By day, Triton is a deckhand on a historic steamship, giving tours of Seattle's maritime history, and their home is a sailboat.

For Triton, the inspiration was the Disney movie The Thirteenth Year, in which a boy grows fins and a tail as he enters puberty. "I loved transformation stories," said Triton. "I wanted that to happen when I turned 13." Like the boy in the film, Triton—who is nonbinary and trans—faced a challenge in establishing their identity as an adult.

"Merfolk don't necessarily have visible genitals, so that can be a thing for trans people," they said. "Triton" isn't just their name—it's the term they use to express their gender. "The two words for merfolk are merman and mermaid," Triton said. "There aren't nonbinary options. I had to come up something on my own."

"I've always kind of been a fish," said Sif, the mermaid I met next to her wheelchair. "I grew up at Norwescon. My parents met at that con. Magic and mythical creatures are things I was always exposed to, and my family gave me the nickname 'Nessie' because when we camped at lakes, I wouldn't want to get out. People had to bring me food and water."

For merfolk, something special happens upon entering water. Reportedly, it goes beyond recreation and relaxation, or comfort, or pleasure. There's a psychological shift that coincides with the ebb of water, something deep and emotional that echoes the physical transformations of mermaid lore.

Everyone I spoke to described a state of intense concentration and focus brought about by their passage into the water. It's the same state that often occurs with music, religion, sex, or sport—and it's been studied by psychologists since the 1970s. The phenomenon is known—perhaps not coincidentally—as "flow."

"I've always been an angry person," said Sif, whose mother took her to be evaluated for behavioral problems when she was a child. A doctor recommended outlets for her seemingly boundless energy—including ice-skating and archery. But there was just something about swimming. "It was like washing it away. For me, water is a calming thing. I can cool down my thoughts, slow down, think logically, or not think at all. It's the most peaceful thing I've ever felt."

Sif added, "The water, it's like home. Like coming home from a really long day and going to bed. I get to completely clear my head and think of nothing but the things that make me happy. And when I come out, I feel cleaned of everything that hurt my head."

Psychologically, flow state is characterized by a deepened ability to concentrate, a dropping of self-consciousness, and a feeling of personal power.

"In the water with my tail on, I feel like I have a lot of power," said Triton.

"It brought out a new level of confidence within me," said Essie. "I feel much more centered. I can feel myself taking on this role. I am a mermaid. I don't see myself pretending to be a mermaid, dressing up to be a mermaid. I see myself as this." The moment she slips into a pool, she said, "I feel much more focused. I feel like a superhero. I'm transforming into my alter ego."

By the standards of most obscure subcultures, the mer community is relatively supportive and tends to avoid scandal and friction. In contrast, the furry fandom is currently struggling with an alt-right wing: Since the election, a small number of furs have embraced a Nazi aesthetic, with red armbands and an #AltFurry hashtag. The gaming community has been trolled by masculine aggressors for years. So far, no such strife has intruded upon the merfolk.

But merfolk have their arguments, too. How can any group of humans (well, half-humans) not? Conflict has arisen when the occasional pool bans tails for being unsafe (which they can be if worn by people inexperienced, impaired, or swimming alone). And of course, plenty of folks have met disdain from family members. But in this particular region of the country, that kind of rejection tends to be gentle and infrequent. "I live in Seattle, and people here just take weird people in costumes in stride," said Triton.

The one significant point of contention? Disputes over tail materials. It's not just an aesthetic issue—economics are a factor. Fabric tails are light and inexpensive; silicone tails are buoyant and look more impressive, but the deluxe versions can cost as much as a used car.

Sif uncomfortably recalled a schism that split local mers a few years ago, when a woman who owned a coffee business wanted to hire mermaids for a publicity event. She advertised for silicone-tail mermaids only, and when she rejected a fabric-tail mermaid, an online flame war broke out in which the business owner was labeled "tailist" and found herself ostracized by certain segments of the mer community.

When I told a friend about this, they openly laughed. That things could get so heated over the material of tails seems absurd. But humans are programmed to form tribes, construct labels, identify enemies, and attack. To outsiders, it's funny and arbitrary and foolish, and indeed our propensity to battle over identity is all of those things. Nevertheless, our dumb primate brains, just barely developed beyond living in caves, can't seem to resist clannish squabbles. We figure out who we are, we figure out who we aren't, and then we know who to fight.

In any case, such squabbles are rare among sea people. Generally speaking, mers maintain a focus on camaraderie, helpfulness, and performing good deeds.

Sif, for example, just obtained a degree in health and recreation. It wasn't easy: Not too surprisingly, her local community college has few course offerings on mermaiding. She's had to adapt coursework that was intended for aspiring personal trainers to focus on her area of interest.

"You're focusing on negatives when you go to the gym," she said. "I very much enjoy helping people enjoy themselves."

She also participates in beach cleanups, coaching young people to understand the importance of environmental stewardship. She'll strategically position herself along a cleanup trail with a trash bag, cheering for kids who pick up garbage.

"For those little kids who want to be at home, going along a beach and then suddenly seeing a mermaid who's asking for trash... something in their brain changes from if their teacher had said, 'Let's pick up our trash.'"

Her voice turned a bit wistful. "There's something about being a magical being, where you have attention that you can use for something. It feels like I can make a real change in the world."

Essie, who just completed her thesis, has similar hopes to change lives for the better. In her policy work, she's forced to think on a very large scale. But, she said, "when I'm in my tail, I think much more locally, much more individually. I think that shift is important not just for me, but a lot of people. Especially people who say they care about the environment. It's not just about systems of power, but also how you personally choose to live your life."

How merfolk live their lives is, to most of us, strange. Yet the impact can be profound—both on their lives and on the lives of those around them.

"When I started performing for kids, I became much more aware that I wasn't doing everything I told them they should be doing," Essie said. Over time, she's become closer than ever to the ocean, through a mixture of her studies and her time with a tail. She's grown more diligent about reducing waste and reusing resources.

These are small, individual acts, of course, but they're also acts of personal morality, illuminated in the most unlikely way: wrapped in a tail and carried in the flow of the substance that makes life on Earth possible.

"This isn't just dressing up," she said. "There's something bigger here."