Mark Zuckerberg and Elon Musk made surprise appearances to the Peninsula this weekend as … crosswalk voice-overs?

In an apparent peculiar stunt, an unknown hacker weaved faked voice-overs of the tech billionaires with satirical messages on the audio tracks of crosswalks in Palo Alto, Menlo Park and Redwood City, according to several videos circulating online this weekend.

A city of Palo Alto employee reported to officials Saturday that a crosswalk at University Avenue and High Street “was not functioning properly,” city spokeswoman Meghan Horrigan-Taylor told this news organization. Officials determined that 12 downtown intersections were possibly tampered with on Friday, she said.

Palo Alto officials disabled the affected crosswalk audible features and checked for other hacked crosswalks. They determined “the impact is isolated,” she added.

“Signal operations are otherwise unaffected, and motorists are reminded to always exercise caution around pedestrians,” Horrigan-Taylor said in a statement.

In Redwood City, Deputy City Manager Jennifer Yamaguma said in a statement that the city was aware Saturday that “a crosswalk signal was hacked, and that a neighboring city experienced a similar incident.”

“Staff were actively working to investigate and resolve the issue as quickly as possible,” Yamaguma told this news organization.

It is unclear how the crosswalk signals were hacked.

A Menlo Park official did not immediately respond to a request for comment Sunday.