If they survive the festival, traumatized animals are rounded up and let out to pasture.
Not much has changed since 2009, despite a growing chorus of protests from animal lovers worldwide. So far, more than 160,000 people have signed one of several online petitions.
"This is another example of man's inhumanity to animals, which I simply can't get my head around," Dominic Dyer of Care for the Wild International said in a release. "Fiestas like this take place particularly in Spain and Mexico with the sole purpose seemingly for people to get their kicks by torturing and killing defenceless animals."
At last year's festival, a bull, as shown by a video posted to YouTube, "got even," knocking over what looks like a concession stand.
It doesn't seem like much of a "get-even" for an animal who is obviously in a state of terror, surrounded and provoked constantly by revelers.
Another video posted to YouTube depicts the chaos of last year's event: A bull is dragged down a slope, tumbling into the water where he thrashes helplessly.