BLACKFISH SeaWorld: roughly as safe as Jurassic Park.

"SEAWORLD REPEATEDLY DECLINED to be interviewed for this film," reads the title card at the end of Blackfish. And there's more: Leading up to Blackfish's release, SeaWorld hired a PR firm in an attempt to aggressively counter the film's most damning claims. It's easy to see why they're so nervous: Once you've seen Blackfish, you'll never go to SeaWorld again.

That's assuming you make it through the movie. With terrifying, nerve-wracking intensity—Blackfish might be a documentary, but it plays like a horror flick—director Gabriela Cowperthwaite examines the role of killer whales in marine parks. She focuses on one killer whale in particular: Tilikum, a bull orca who lives at SeaWorld Orlando. Graceful and majestic, Tilikum is 32 years old, 23 feet long, and weighs 12,000 pounds. He's killed three people.

Like The Cove—a similarly brutal documentary from 2009, about Japan's relentless dolphin slaughter—Blackfish will change the way you think. It isn't perfect, thanks to a sappy score and a forced ending, but in lining up testimony from researchers, activists, and passionate but disillusioned former SeaWorld employees, Cowperthwaite makes a case that's impossible to reasonably ignore. Places like SeaWorld, Blackfish asserts, can't help but fuck whales up. ("Could you imagine being in a small concrete enclosure for your life when you're used to swimming 100 miles a day?" says former SeaWorld trainer Jeffrey Ventre.) And when whales get fucked up, they lash out—attacking each other and, in a shockingly large number of incidents, humans. Blackfish centers around the death of one of Tilikum's trainers, Dawn Brancheau, but the video and recollections span other attacks, despite some footage being "lost" by SeaWorld: a woman remembering how her fiancé was killed by an orca at a marine park in Spain; a man pulled, again and again, to the bottom of a pool; a dazed woman stumbling from the water, her arm drooping in a sickening U. Watching Blackfish, one realizes SeaWorld has their work cut out for them: There isn't any way to spin this that's anything less than horrific.