The cellphone vibrated softly, insistently, echoing off the whitewashed walls of the artist’s studio. It was a Sunday morning in early April, and Wang Bo — an Internet animator better known to his legions of online fans by his nickname, Pi San — ignored the call at first. He wanted no intrusions. A compact 40-year-old with short-cropped hair and arched eyebrows that give him a look of permanent bemusement, Pi San is most famous for creating a mischievous cartoon character named Kuang Kuang, but he earns money by making animations for corporations, and he was on a deadline. Pi San had bicycled to his studio in a defunct factory building on the outskirts of Beijing that morning, hoping to finish up some work in peace. But the buzzing of the phone didn’t stop.