Donald Trump intended to restart his campaign in Tulsa with a spectacular event. He confidently claimed that one million people had requested tickets for the event. It would be incredible!

The plan was for Trump and Pence to speak at an outdoor rally for 40,000 people, then move indoors to the BOK Arena to speak to a packed house of 19,000 people.

But the outdoor rally was canceled when only a few dozen people showed up. Inside the arena, according to the Tulsa Fire Department, there were fewer than 6,200 people. The entire upper deck was almost completely empty.

What happened to the Trump base? Why did the campaign say that one million people had requested tickets?

The New York Times credits activist teens, who sabotaged the Trump rally using social media to urge contemporaries to flood the campaign with requests for tickets.

TikTok users and fans of Korean pop music groups claimed to have registered potentially hundreds of thousands of tickets for Mr. Trump’s campaign rally as a prank. After the Trump campaign’s official account @TeamTrump posted a tweet asking supporters to register for free tickets using their phones on June 11, K-pop fan accounts began sharing the information with followers, encouraging them to register for the rally — and then not show.

The trend quickly spread on TikTok, where videos with millions of views instructed viewers to do the same, as CNN reported on Tuesday. “Oh no, I signed up for a Trump rally, and I can’t go,” one woman joked, along with a fake cough, in a TikTok posted on June 15.

Thousands of other users posted similar tweets and videos to TikTok that racked up millions of views. Representatives for TikTok did not immediately respond to requests for comment.

“It spread mostly through Alt TikTok — we kept it on the quiet side where people do pranks and a lot of activism,” said the YouTuber Elijah Daniel, 26, who participated in the social media campaign. “K-pop Twitter and Alt TikTok have a good alliance where they spread information amongst each other very quickly. They all know the algorithms and how they can boost videos to get where they want.”

Many users deleted their posts after 24 to 48 hours in order to conceal their plan and keep it from spreading into the mainstream internet. “The majority of people who made them deleted them after the first day because we didn’t want the Trump campaign to catch wind,” Mr. Daniel said. “These kids are smart and they thought of everything.”

Brian Stelter of CNN had the story. A grandmother in Iowa named Mary Jo Laupp posted a video on Tik-Tok that encouraged viewers to order tickets to the rally, but not show up. She says she had only 700 followers but the video went viral and reached at least 700,000 viewers. She thinks that a great many young people took her advice, even teens too young to vote.

No one knows for sure, but many requests for tickets may have been generated by Laupp’s video. That may explain why the campaign expected hundreds of thousands to pour into Tulsa.

Trump must have been shaken by the humiliatingly meager turnout. His performance was lackluster. The old lines didn’t work anymore. He can’t say “Build the Wall and Mexico will pay for it,” because even diehard Trumpers know that Mexico will not pay for it. He can’t say “Lock her up!” because that’s ancient history. He can’t lead chants of “Drain the Swamp” because he has created his own Swamp of lobbyists and put them in charge of federal agencies.

All he has left in his arsenal is divisiveness, rage, racism, and nativism. His most militant fans will stick with him to the bitter end, clutching their Confederate flags. To most Americans, he has become a menace, a national embarrassment, and a humorless bore.

Four more months.