Police responded to two large, overnight sideshows in Vallejo and Oakland.
Huge crowds gathered in Vallejo at around 11 p.m. Saturday in the area of Columbus Parkway and Georgia Street.
About 100 spectators blocked the road as they watched the dangerous stunts in the middle of the intersection.
Police said they broke up the crowds in about 20 minutes. They arrested at least four people and impounded a car.
Then a few hours later, another sideshow popped up in Oakland near 90th and MacArthur.
Oakland police were seen a block away, monitoring the crowds.
Video captured what sounded like gunshots, coming from the area of the sideshow.
NBC Bay Area reached out to Oakland police Sunday for more information on any possible arrests, but have not heard back.
Source: NBC Bay Area