In June, Amir Pleasants, a 21-year-old resident of Montclair, N.J., matched with someone new on Tinder. But after he and the woman, Natasha Aponte, sent a few messages back and forth, she abruptly cut off the exchange.

She told him that a work project was going to be taking up a lot of her time and that she would get back to him in a couple of weeks. He didn’t expect to hear from her again.

Then, last week, she contacted him, and told him to meet her for a first date in Union Square in Manhattan on Sunday. A friend of hers was D.J.-ing a set, and she wanted to get drinks in the area afterward. He was thrilled, texting her “I’m so excited, this seems too good to be true lol. You are absolutely stunning.” He punctuated the message with the heart eyes emoji.

The following evening, he drove into the city, arriving around 6:15 p.m.

“I get there and there’s probably 150 to 200 guys outside,” he said in an interview Monday. “All kind of looking at each other trying to figure out the situation. That’s when we know we kind of got set up.”

Ms. Aponte, who could not be reached for comment, had used Tinder to stage a pop-up dating competition — complete with a stage, an occasionally malfunctioning microphone and a video team, stationed in the northern plaza of Union Square. Those interviewed the following day told stories that were nearly identical to the one Mr. Pleasants shared.

Connor Murray, 22, was planning to attend but started to feel sick on Saturday night. On Sunday morning, he was one of many people to receive a reminder text from Ms. Aponte. She said that even though the forecast was iffy, their date would go forward, rain or shine.

That struck Mr. Murray as odd. “Who the hell says rain or shine on a first date?” he said. Still feeling sick, he decided against going.

Many of the men who did show up lived in the area, but Mr. Pleasants said that he talked to some who were from as far away as Oregon.

As promised, there was a D.J. playing when the men arrived. Around 6 p.m., Ms. Aponte was nowhere to be seen but some men, including Misha, 30, whose Twitter thread about the scam took off online, received texts from Ms. Aponte saying she was running late.

Then, as the D.J. finished the set, a woman dressed in all black took the microphone and introduced herself simply as Natasha.

“I have a confession to make,” she said. “Everyone here today was brought here to be on a date with me.”

Like ... a group date?

She explained that she was over dating apps and wanted instead for her suitors to participate in a competition. She would go on a date with the winner.

She disqualified outright the men who were shorter than 5 foot 10, who were named Jimmy (she dislikes the name) or who had been dumped in their previous relationship, making the rose ceremonies on “The Bachelorette” look generous.

Of those who made it past the initial screening Ms. Aponte requested 30 push-ups on the spot.

She then asked the men to line up, and she “swiped left” on anyone she did not want to advance to the next round. She also asked them to race each other and gave each man about a minute to explain why he wanted to be with her.

Mr. Pleasants said that he was a little “too prideful to hop in that line,” but that there was an eventual winner whose name he did not catch.

Still, Ms. Aponte’s stunt was engineered for a purpose other than getting a date. 
The D.J. who played before she took the microphone, Nick AM, said in an email that he had signed a nondisclosure agreement. But he later directed questions to Rob Bliss, the mastermind behind an infamous catcalling video that was viewed more than 47 million times after being posted in 2014.

Mr. Bliss said that he was involved with the stunt, and said that a video would be released on Thursday explaining the “who/what/why/etc. and the story of everything that happened.”

He declined to comment on whether he was surprised by one result of the event: That it unleashed a wave of anger from those duped into showing up. Ms. Aponte was compelled to ignore obscene chants as she organized the competition. Later on Sunday, she took her Instagram account private after receiving dozens of comments calling her names.

"I can’t believe this girl did this to so many innocent men,” one commenter said. “There were guys with flowers and letters, excited to meet her. Their faces were covered with sadness when she announced the truth.”

Misha, who declined to give his last name but insisted he had not collaborated with Mr. Bliss, said that he was not sure how to feel about the stunt a day later. (He was one of the men who refused to compete.) He said that it was funny, and “obviously successful,” but that it was also a sign of the times. He sympathized with reporters trying to frame the story.

“I don't know how I would frame it either,” he said. “It’s very funny and very dark at the same time.”