A routine keynote address by Baidu Inc. chief Robin Li morphed into a public humiliation when an unidentified man jumped onstage and doused him in water.

The billionaire founder was 10 minutes into introducing an AI-powered valet parking service when a man in a black T-shirt upended a small bottle of water over his head. The Chinese internet tycoon froze in place for a few seconds, wiped his face, then plowed ahead with his speech as if nothing had happened.

"What's your problem?" Li said in English to the perpetrator, who was wearing an event pass. "As everyone has just seen, there will be a variety of unexpected happenings on the road to AI," said the CEO, who was headlining a Baidu artificial intelligence developers' forum in Beijing.