The grizzly bear whom Will Ferrell playfully wrestled in his recent movie "Semi Pro" went on the attack Tuesday, killing his trainer with "a single bite to the neck" and potentially putting its own life in danger, as animals officals decide whether to euthanize the animal.
The bear named Rocky is 7 feet tall and weighs 700 pounds. Without warning, the seemingly tame bear's killer instinct kicked in as three experienced trainers were working with him at a facility east of Los Angeles.
"He, unfortunately, bit one of the trainers," Maurice Moore of the San Bernadino Fire Department said. "A single bite to the neck, no aggression acts to follow."
Rocky attacked 39-year-old Stephan Miller, who died before emergency help arrived.
"San Bernadino Big Bear City was the first on scene," Moore said. "They did CPR but to no avail."
Other trainers used pepper spray on Rocky and contained the animal.
Miller worked with his cousin and famed animal trainer Randy Miller at Predators in Action, the training facility owned by Randy.
Though representatives from the California Department of Fish and Game, which will likely determine whether Rocky is euthanized, did not immediately return calls for comment about the bear's future, several wildlife experts told ABCNEWS.com that he should not be killed.
"Of course these attacks are tragic, but we shouldn't be messing with these animals in the first place," said Mark Bekoff, a professor of ecology and evolutionary biology at the University of Colorado and author of "The Emotional Lives of Animals."
"You can't just use these animals for what you want them to be and then kill them because they act as the beings they are," said Bekoff, who added that bears and all animals should not be used as actors anyway.
"[Bears] are wild animals and no matter how they're kept or treated or trained this is a huge reminder that they have natural instincts and tendencies," said Debbie Dawson, the National Animal Control Association spokeswoman.
Bekoff suggests that Rocky be placed in a sanctuary – not a zoo – where he can "live out his life in dignity."
In a February interview, Randy Miller called Rocky "the best working bear in the business," the San Bernardino Sun reported on its Web site today. But the paper quoted him as saying, "If one of these animals gets a hold of your throat, you're finished."
Why Rocky attacked is still under investigation. The Millers have worked with animals in nearly 20 films and have 25 years of experience.
Their Web site claims the company "has a perfect safety record with absolutely no accidents or mishaps." The site also claimed that Randy doubled for Ferrell in the bear wrestling match.
Randy Miller won a World Stunt Academy Award for his work wrestling ferocious tigers in the 2000 blockbuster "Gladiator" and performed stunts with his animals in films like "The Postman," "The Island of Dr. Moreau" and "The Last Samurai."
He also helped recreate animal attacks for National Geographic documentaries and the Discovery Channel. Most recently he provided tigers for the movie "First Fear," due out later this year.
The Associated Press contributed reporting to this story.