The bull's escape in the town of Gilet occurred Monday during the San Anton festival, which is marked by the blessing of the animals, ThinkSpain reported Tuesday.
Witnesses said the bull used his head to break down a barrier in his enclosure, which was set up in the town's main street. He then ran down the street, with spectators fleeing from him. He dented four cars.
Five spectators sustained minor injuries, including twisted ankles and bruised ribs. Two of them were treated and released at a hospital.
Some 100 spectators formed a human chain and helped herd the bull into his enclosure until event organizers could lasso the bull and load him into a truck.
A scheduled bull-running event was canceled.