AI is the new Grinch that’s stealing Christmas. Nervous laughter was Kelly Bowron’s visceral, hysterical response to her son learning the truth about Santa Claus Tuesday — courtesy of a Google search.

It started with a boy in her class—some kid with a loose tooth and loose lips—who told her Santa wasn’t real. “It’s just your parents,” he said, as if he were reporting tomorrow’s lunch menu. My ...