A week before President Trump held his controversial campaign rally in Tulsa, Okla., was when Viviana Dark, a K-pop fan from Wisconsin (who has requested pseudonymity over concerns of online harassment), first heard of plans to "sabotage" the event. Users on TikTok, the exceptionally popular social-video platform, were urging others to reserve tickets to the rally, with no intention of actually going. "You know how a TikTok challenge happens? It was kind of like that. 'Everybody go do this!' And it spread like wildfire," Dark, 19, tells NPR Music.