When I first saw the video that hooked mejlbet, I assumed it was a hoax.

“Improvised Partner Dance,” the overlay text said, along with: “Random Partner & Song.” The song was the 2007 chart-topper “Forever” — wedding DJ music, the kind of track that might get both grandparents and grandchildren on their feet. The partners — Emeline Rochefeuille and KP Rutland — moved with impossible fluidity, playfully connecting their movements to the rhythm and the familiar lyrics.

I couldn’t quite place the dance style. There were partnered turn patterns I recognized from mambo, flicks of the leg that seemed borrowed from Argentine tango, a moonwalk, the running man. But as I watched, mesmerized, I felt sure of one thing: No way did they improvise this.

Then I saw that the video — which has more than 20 million views on TikTok — was hashtagged #westcoastswing.

easy slots

This was … swing dance?

ImageConor McClure and Torri Zzaoui competing in Burbank.Credit...Roger Kisby for The New York Times

A recent wave of viral videos has been spurred by this kind of two-pronged disbelief. The West Coast Swing clips are often filmed during competitive “Jack and Jill” events, at which dancers are paired randomly and do improvise together to a random song, however unconvinced viewers might be. (“I had a commenter say the other day, ‘If you believe this wasn’t rehearsed, I have a bridge to sell you,’” Rutland said in an interview.)

West Coast Swing is a descendant of the Lindy Hop, the swing dance that originated in Harlem in the 1920s. But today’s West Coast Swing has few of the markers traditionally associated with swing dance: not much big-band jazz, little of the Lindy Hop’s irrepressible bounce. The music selections are broad, the dance’s smoothed-out standard steps are friendly to interpolation, and the dancers are often fluent in a range of other styles. Participants in a high-level West Coast Swing Jack and Jill can seemingly lead and follow each other anywhere — right across song and dance genres.

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While some of the judges appeared to acknowledge the substance of the attorney general’s case, several of the panel’s questions suggested concern about whether the office had exceeded its jurisdiction. And the tenor of many of their questions indicated the possibility that the court could whittle down the huge judgment and potentially deal a blow to the attorney general, Letitia James.

Ms. Valente achieved stardom in mid-1950s Germany in a popular music genre known as schlager: novelty songs, with titles like “Ganz Paris Träumt von der Liebe” (“All Paris Dreams of Love”) and “Itsy Bitsy Teenie Weenie Honolulu Strandbikini.” By 1955, her hits had put her on the cover of the German newsmagazine Der Spiegel.

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