Early childhood dislocation trauma.

Routine child abuse.

Repeated victim of bullying.

Dissociative social disorders and anti-social behaviors.

Trauma-induced psychosis.

What does that sound like?

If you said, “The common background factors of serial killers, spree killers and school shooters everywhere,” you would be correct. You would also be correct if you answered, “The life of Tilikum, a captive orca.”

Gabriela Cowperthwaite’s documentary Blackfish is a startling, disturbing, moving portrait of the male orca known as Tilikum, who currently resides at SeaWorld Orlando. In a larger sense, the film documents orca captivity, but the story often bypasses opportunities to expand the view on SeaWorld and captivity in favor of continuing to focus on Tilikum, who, at six tons, is the largest captive orca. The narrow focus on Tilikum and his troubling past—he has killed three people during his thirty years in captivity, most recently Dawn Brancheau in 2010—serves the film well, though, as Tilikum becomes an allegory for orca captivity. With Tilikum front and center, it would just be redundant to hammer the point home with multiple orca protagonists. Tilikum’s story is more than enough.

I went to SeaWorld when I was kid and I fell in love with the killer whales. It’s impossible not to—they’re awesome creatures, in the truest sense of the word. I wanted to be a marine biologist and study orcas for years and years, until sophomore chemistry crushed that dream. I still love them, though, and one of my life-long dreams is to see wild orcas. This is the paradox of Blackfish—our desire to protect killer whales stems from our ability to see them up close. It’s an unaddressed angle that would have deepened the film’s position on orca captivity—at one point a former SeaWorld trainer deems it “barbaric”—but it’s also exactly the kind of sidebar the film lets pass by in favor of Tilikum’s narrative. It’s enough that half a dozen former trainers all walked away from SeaWorld with the conviction that orca captivity is wrong for a myriad of reasons (they’re too big, too social, too sensitive, too intelligent).

As a documentary, Blackfish succeeds on every level. It’s informative, compelling and thought-provoking, and though it’s blatantly anti-captivity, it’s not manipulative like The Cove was; that’s a good documentary, too, but it’s definitely trying to make you feel and think a specific way. Blackfish simply tells Tilikum’s story, explaining elements along the way, like how wild orcas are captured—which will make you cry—and the conditions in which he was first kept and trained—which will also make you cry—and how the natural social order of orcas is perverted by captivity—which will also make you cry. By the end of it, it’s hard not to agree that orca captivity needs to end.

Plenty of examples are given of how SeaWorld misrepresents captivity, claiming that captive orcas lead long healthy lives, when, in fact, everything scientists know about wild orcas contradicts that. (SeaWorld issued eight rebuttals to the film, which the filmmakers addressed.) The only thing you really need, though, is the final image of Tilikum, alone in his tank, floating in place as a voice off camera says, “That’s three hours he’s just been floating there.” Or the story about the mother orca separated from her calf, and how she emitted vocalizations no captive orca had ever been observed making, vocalizations a specialist said were meant for long-range communication. The implication of a mother screaming for her missing child is heartbreaking and stomach-turning.

For all that Blackfish is a sterling documentary—and it is—it’s also a chilling psychological thriller. Tilikum’s story starts with kidnap and abuse and ends in murder. How a creature that, when observed in the wild, is friendly, inquisitive, even playful, end up a thrill-killing murder beast is the kind of character arc you’d expect to see in a Quentin Tarantino movie. And the corroborating evidence, cases of other killer whales attacking, or “pulling” as the trainers call it, is brutal and horrifying. The footage of an orca repeatedly dragging a trainer to the bottom of the tank and holding him there, slowly drowning him, is the most frightening sequence I’ve seen in any film this year.

But Tilikum is as much victim as instigator. This isn’t a hit piece against an animal but against the conditions that made it possible for Tilikum to become aggressively dangerous and for Brancheau to be in a position to be hurt (the documentary also details the OSHA lawsuit that followed Brancheau’s death which ended with SeaWorld having to cease performing “water work” tricks which put trainers in the water with killer whales, though SeaWorld is appealing that ruling). Tilikum’s story is sad and tragic and gruesome, and Blackfish is a deeply upsetting film. It’s a must see.

Tilikum still performs at SeaWorld daily.