This time, PizzaGate is being fueled by a younger generation that is active on TikTok, which was in its infancy four years ago, as well as on other social media platforms. The conspiracy group QAnon is also promoting PizzaGate in private Facebook groups and creating easy-to-share memes on it.

Driven by these new elements, the theory has morphed. PizzaGate no longer focuses on Mrs. Clinton and has taken on less of a political bent. Its new targets and victims are a broader assortment of powerful businesspeople, politicians and celebrities, including Mr. Bieber, Bill Gates, Ellen DeGeneres, Oprah Winfrey and Chrissy Teigen, who are lumped together as part of the global elite. For groups like QAnon, PizzaGate has become a convenient way to foment discontent…

In the first week of June, comments, likes and shares of PizzaGate also spiked to more than 800,000 on Facebook and nearly 600,000 on Instagram, according to data from CrowdTangle, a Facebook-owned tool for analyzing social interactions. That compares with 512,000 interactions on Facebook and 93,000 on Instagram during the first week of December 2016. From the start of 2017 through January this year, the average number of weekly PizzaGate mentions, likes and shares on Facebook and Instagram was under 20,000, according to The Times’s analysis.