Dominic Chow of Malaysia and Dinell Holmes of Pittsburgh, Pa., face off in a round of Pokemon at the Pokemon World Championship on Aug. 15 at the Washington Convention Center. (Photos by Jessica Contrera/The Washington Post)

The tail of the whale is dragging on the convention center floor, and everyone is looking.

It is attached to a full-body costume made of blue felt that was carefully measured and velcroed to fit its owner, a 12-year-old boy named Theo Chevis. Theo is hoping to get years of use out of the whale costume, so he ordered it to be a little big. He doesn’t mind the way it drags; he has a tournament to think about.

The costume, you see, is not a whale at all. It’s a Kyogre, a whale-like character from Pokemon. One of the strongest Pokemon characters to exist, he says. “A true behemoth, really.” The fuzzy fabric took up more than half of Theo’s suitcase when he and his dad flew all the way from London to Washington, D.C., for the Pokemon World Championship, which is taking place at the Washington Convention Center through Sunday.

On Friday morning, Theo’s dad had left him to his own devices in the world he loves. As he makes his way to the concession stand, Pokemon players stop their card trading and point to Theo, the 5-foot Kyogre. The hood of the too-large costume covers Theo’s eyes, but he pushes it up to see a bald man giving him a thumbs-up. “Wow, that’s amazing!” the man says. “Way to go.”

An attendee at the Pokémon World Championship photographs Theo Chevis, 12, who came from London to play and observe in the event that is expected to draw more than 2,000 people. An attendee at the Pokemon World Championship photographs Theo Chevis, 12, who came from London to play and observe in the event that is expected to draw more than 2,000 people.

This was the day Theo had been waiting for ever since he ordered his custom-made costume from (without his mom’s permission). More than 2,000 Pokemon fans, gathered in one place for the most important tournament of their year.

There’s the Pokemon trading cards, which debuted in 1996 and are still seen as the core of true Pokemon fandom. And now almost equally important is the Pokemon video game, the reason Theo is here. Both remain popular enough that to compete in the World Championship, players must accumulate between 400 and 500 points, depending on their age. Points are gathered by competing in other tournaments throughout the year. Gathering enough points is intentionally difficult; even if a player comes in first place in the tournament of their city and their state, they still only have 150 points.

For some players, that means spending nearly every weekend of the year at Pokemon tournaments. For Theo, it means his chances of actually competing in the championship are slim.

His one remaining chance is an afternoon tournament in which 75 kids will compete for four spots in the video game championship for Theo’s age group.

He is about two hours away from the start of that tournament when he makes it to the concession stand. Time to fuel up. He pulls out the American money he is keeping tucked into his registration form, and with no parent watching, buys barbecue chips and a Mountain Dew.

Theo Chevis buys snacks at the Washington Convention Center during the first day of the Pokémon World Championship. Theo's costume, which he designed and paid for himself, is of the Pokémon character Kyogre. Theo Chevis buys snacks at the Washington Convention Center during the first day of the Pokemon World Championship. Theo’s costume, which he designed and paid for himself, is meant to be the Pokemon character Kyogre.

“Thank you,” he says in his 12-year-old British accent. He says it again a few minutes later, when someone yells “Woah!”

“Can I take a picture?” asks the admirer, who looks college-aged.

“Alright,” Theo says. The fins of the Kyogre are sewn on like butterfly wings, so he spreads his arms wide and looks at the phone’s camera.

“No, with you, man!” the guy says, then kneels down in front of Theo to take a selfie.

Theo is one of the only ones in full costume, which makes him stand out even among the throngs of people in Pikachu hats. The attendees come from 30 countries and represent every age between 6 and 60, according to one tournament organizer.

“These are the most incredible people,” Theo says, entering the game hall where a giant inflatable Pikachu is hanging from the ceiling. In London, no one quite appreciates the way Pokemon makes him feel. At school, the kids are all about football (soccer in America) and “shoot-em-up games,” he says. Of the 14 kids in his class, only one, Alexander, likes playing Pokemon. And because he isn’t allowed to take his pink Nintendo 3DS out of his backpack during school hours, Theo and Alexander spend recess standing and discussing their characters.

But here, everyone gets it. So it was worth saving up his allowance money to spend 124 pounds on a custom-made Kyogre costume.

Maybe it will bring him some luck. If he places top four in the last-chance tournament and gets to enter the World Championship that begins Saturday, he could win a $3,500 scholarship, a trophy and, best of all  he’d get to come back next year.

Waving at a girl in a Charizard hat who is pointing and smiling at his tail, Theo sits down at a table and opens his Mountain Dew.

One hour and 40 minutes to go.

He is nervous. But he is a Kyogre, and he is ready.