An absurdist joke is spreading across Twitter in a viral pattern. No one has control, no one is safe, and after two days, the contagion is still growing. The virus will likely hit your stream soon if it hasn't already, but it's not so easy to spot — it looks like any other normal tweet. "Wow," it reads, with a link. But click that link, and it will lead to another person's tweet. "Wow," this one says, with a link. That link leads to another tweet, from someone else. "Wow," this person says, appending a link.

It's wows all the way down.

The beauty of this game is that everyone joined in without knowing the rules. "I have no idea. I just saw it and played along," Alex Godin, a 19-year-old startup founder based in New York, said in a Twitter direct message. "I did have the patience to click through to the end... and it's just a disappointing Donald Trump tweet about 'Shark Tank.'"

Indeed, the tweet at the end of the chain is from the real estate mogul and reality television star, spouting some typical self-promotional drivel. "Shark Tank is a dead Friday night filler compared to the Apprentice which has been number one show for week in the T. V. ratings!" Trump grumped at 8:02 p.m. on Monday.

Mark Gurman, a senior editor at the Apple blog 9to5Mac with 11,957 followers, tweeted a link to this comment, prefaced with the word, "Wow." Gurman was patient zero. He had no idea what he'd started. "I didn't intentionally start the chain, and I wasn't expecting it," he told The Verge in an email. "I actually saw the chain fairly early on, I clicked through and realized that it ended at me (surprise)."

Erik Schmidt, a student in Arizona, had a funny idea. He tweeted the word, "Wow" followed by a link to Gurman's tweet. Days later, he was amazed that the joke had traveled all the way to the Middle East and back. "How far has this gone?" he asked followers yesterday. "How far has this traveled?" Patient one.

Schmidt's tweet was picked up by a Twitter friend, a student who lists his name as Paco. This was patient two. Even though he only has 186 followers, Paco's stream shows he's up on all the latest microblogging trends, including SnapChat, subtweeting, and tweeting about tweeting. He quickly caught on to the half-formed joke, and tweeted Schmidt's tweet with the identical format. He was just as surprised as Schmidt when he tried to reconstruct what had happened. "What the actual eff. Are we famous now?" he asked a Twitter user named Jamil, patient three.

This is where the tree branch splits. Two Twitter users, named Mark and Danny, copied Jamil's tweet. Together, they have just over 600 followers. This was truly a grassroots movement. No one tweeted Danny's tweet, but two people picked up Mark's: Conor Reid, who tweeted it to his 1,375 followers, and Brandon, who tweeted it to his 298. No one tweeted Brandon's tweet, but four people picked up Conor's: Tyler Flowers (454 followers), Alex Dixon (1,308 followers), Zayd Humsy (206 followers), and Eugene Ho (133 followers).

Tyler got a tweet from Jorge Danny, 1,244 followers. No one tweeted Alex's or Eugene's tweet. But Zayd got three tweets, from James Gordon (207 followers), Avery Penn (530 followers), and Eva Giselle (3,490 followers). No one tweeted James's, one person tweeted Avery's, and a whopping 13 people tweeted Eva's tweet. It was unstoppable now.

Ben Jacobs, a New Yorker with 1,306 followers, caught the beginning of the "wow" chain when it was about a dozen tweets long and traced it back to Gurman. "I'm very surprised it took off like it did," he said in an email. "If I remember right, the Gurman tweet had one retweet and favorite each when I found it, I think I was the second person to favorite it. Honestly, I think the whole thing is pretty dumb. If I was annoyed... the day after, I can only imagine what folks are feeling now. This is the first I've encountered anything like this but I doubt it'll be the last after how it's caught on.

"It's really bizarre," he continued. "I joked yesterday that some company will co-opt it like Viacom did with 'hacking' recently and now I'm afraid that'll actually happen."

The trend hasn't been coopted by corporations yet, but it's still going strong, even reaching as far as the Arabic-speaking world, where Twitter users changed the opener to "woow." Users seem happy to jump into the game with no context — for people embedded in the Twitter world, the behavior is instinctive, even though no one can recall seeing something like it before. The closest inception-like meme is perhaps "the old Reddit switcheroo," in which an exhaustively long chain of images with swapped captions kept users clicking for hours. Meanwhile, Donald Trump continues to tweet blithely about his show's ratings.