Mind control. Satanic rituals. Unspeakable sexual perversions. Supervillains eating children's brains. A divine mandate to keep Donald Trump in the White House, no matter what. This surreal combination of horror-movie shocks and fascist marching orders is the signature of QAnon, which emerged from the dark corners of the internet in 2017 and soon became the galvanizing force behind Trump supporters, both during Trump's...