Thousands of fans illuminated the Volksparkstadion in Hamburg, Germany, on Tuesday with a new Eras Tour trend, 10 shows in the making.

As soon as lightning flashed and thunder roared following "Marjorie," Taylor Swift smiled into the stadium cameras and waltzed to the back of the stage to begin the "Evermore" chant: "Wait for the signal, and I'll meet you after dark."

Swifties from every section of the stadium blew up orange and yellow balloons and started their phone flashlights to create their own "Willow" orbs, mimicking the dancers' light-up props onstage. Rain pattered down from the open-roofed arena.

How the 'Willow' trend began

Life was a willow and it bent right to the breeze of three Amsterdam Swifties.

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Coralisa Meijer, 22, Charlotte Lanser, 24, and Samantha Davelaar, 25, walked into the Johan Cruijff Arena on July 4 with three yellow balloons and a bright idea. As Swift sang "Willow," they bobbed and waved their dollar-store orbs in the nosebleed section high above the throng of screaming fans.

"We had some extra space in Amsterdam," said Lanser over Zoom. "We were like, it will just be a fun little thing for us to do."

"Then we thought let's put our flashlights on," added Meijer. "And it just kind of happened, and people started filming us from the other side of the stadium, and it went viral."

Little did the trio know their novel idea would receive a shoutout from Swift seven shows later in the Veltins-Arena of Gelsenkirchen, Germany.

"There have been people bringing balloons to the Eras Tour to make their own orbs for 'Willow,'" Swift said to the crowd during her acoustic set. "I was cracking up the whole time. You guys are so thoughtful."

On the final night in Gelsenkirchen, the three friends dressed as clowns were invited to the VIP area on the floor —dubbed the Red Lounge — by the singer's team. They witnessed firsthand hundreds of fans blowing up their balloons and lighting up the arena.

"I get goose bumps every time I see it now," Meijer said.

"Sometimes we cry," Lanser added. "'Willow' has become one of our favorite songs within the past few weeks."

Swift liked a recent reel on the trio's combined Instagram page. A video showing how the craze started and how it's going has been viewed more than 400,000 times.

"I hope she knows how much we love her," Meijer said. "I hope she is happy every time she sees the lights, and I hope she knows that she makes friendships happen."

Swiftie impacts on the Eras Tour

The "Willow" trend is only the latest of many chants, props and crazes inspired by fans along the Eras Tour. Swift mentioned the thoughtfulness in Hamburg.

"You have so many traditions that you guys have totally made up — and we already had a lot of them when we got to the European tour — but you guys recently have been coming up with so many new things, like traditions on this tour," she said. "It's amazing. Thought I'd seen it all, and then we got to Germany."

Here is a list of some of the appended traditions not included in previous tours:

• "Lover" construction paper hearts: Fans hold pastel and vibrant pieces of paper cut into heart shapes during her seventh era title track song.
• "Love Story" proposal: Engagements have happened at concerts around the world during the "Fearless" song. Swifties have gotten down on one knee to pop the question when Swift sings the bridge line, "He knelt to the ground and pulled out a ring / And said..."
• "We will stay" signs: During "Archer," a song cut from the second year of the Eras Tour, fans would print signs and hold them up in the audience that said, "We will stay." The signs answer one of the song's lyrics that asks, "Who could stay?"
• "All Too Well" question: When Swift sings, "You said if we had been closer in age, maybe it would've been fine," to which fans respond, "How did that make you feel?" The "Red" singer answers with her lyric, "And that made me want to die."
• "Champagne Problems" standing ovation: When the singer finishes her "Evermore" acoustic song on the piano, fans start timers and scream as loud and long as they can to show appreciation of Swift. She mouths, "Thank you," "Wow" and "That's so loud" as she takes out her ear monitors. The tradition has incited competition between cities to see how long they can go before the singer speaks. On Aug. 8 in Los Angeles, fans kept cheering for almost eight minutes.

• "My Tears Ricochet" question: Influencer Chris Olsen yelled over a TikTok live in Tokyo, "Who's Grace?" after Swift sings the line, "I didn't have it in myself to go with grace." The funny quip caught on and is a response fans will yell during the devastating song.
• "Marjorie" phone lights: To pay tribute to Swift's grandma "Marjorie," fans turn on their phone flashlights during the "Folklore" song.
• "Style" question: In Atlanta, @starbornn.readeron TikTok shared a video shouting, "Hey Taylor, what time is it?" to which she sings "midnight / You come and pick me up." The video has 11 million views.
• "Blank Space" chant: In the 1989 World Tour movie, Swift grabbed an iron golf club and hit a metal pole sticking out of the stage. She paused and did it again before singing: "Syd-ney." The singer filmed the movie in 2015. When she brought the Eras Tour to the Australian city, the fans sang the chant back. "By the way, do you know how cool it was when I was singing 'Blank Space,'" she said to the 81,000 fans in Accor Stadium. Taylor Nation, Swift's in-house marketing team, tweeted shortly after that they wanted every city to scream its name.
• "Bad Blood" chant: On night two in Philadelphia, Swift defended fan Kelly Kelly in between the lines of her "1989" song: "She's fine. She wasn't doing anything. Hey stop! Hey stop!" Fans recite the Philadelphia version at shows. Swift's team invited Kelly to the VIP tent the next night.
• "Anti-Hero" lyric change: In the "Anti-Hero" remix featuring the Bleachers, Jack Antonoff's band, he sings "Taylor, you'll be fine" instead of her original lyric of "tale as old as time." Fans sing Antonoff's version during the "Midnights" track.
• "Bejeweled" question: Instagram fan Tyler Conroy shared a reel from the Houston Eras Tour where he shrieks, "Where you going, Taylor?" before she says, "I'm going out tonight." The funny exchange caught on and fans echo the viral video.
• "Karma" lyric change: During Travis Kelce's first Eras Tour concert as Swift's boyfriend, she changed the lyrics to: "Karma is the guy on the Chiefs coming straight home to me." She only sings that lyric when the tight end is in the crowd and — even though she's performed it only 13 times — the crowd sings the boyfriend shoutout every night.

Swift has one more show in Hamburg, Germany, on Wednesday and two shows in Munich, Germany, this weekend.

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