Twenty years ago, when Buffy the Vampire Slayer debuted on The WB, it’s hard to imagine anyone conceiving of what a phenomenon the show would become—a hit TV series, yes, but also a platform through which pop-culture theorists and sociologists alike could consider the dynamics of American teenaged life around the turn of the millennium. “Buffy Studies” have become a thriving faction within academia, while streaming services have kept the show on the contemporary cultural radar. In a media landscape where people continue to be surprised that teenaged girls engage with political issues, the idea of a perky blonde cheerleader being tasked with saving the world is still strikingly subversive.

One of the most revolutionary things Buffy did, though, was take teenagers—and their pain—seriously. The show’s central conceit of having Buffy (Sarah Michelle Gellar) be a “chosen one” destined to protect the earth from vampires and monsters offered a fairly typical setup for a supernatural drama, but the twist was that many of Buffy’s boogeymen were based on real sources of teenage angst. Here were metaphorical demons made literal: a controlling mother who lives vicariously through her daughter, a friend whose behavior becomes unrecognizable when he joins a pack of popular kids, a classmate so lonely and isolated she becomes literally invisible. By having intangible issues manifest themselves as physical monsters, Buffy made them accessible, and manageable.

As the show progressed, its creator, Joss Whedon, experimented more with the boundaries of what Buffy could do. In season four, concerned that the show’s great strength—its dialogue— was overriding its other qualities, he wrote an episode, “Hush,” in which every single character lost their voice. In season six, he conceived a musical episode in which the characters found themselves spontaneously bursting into song. And in season five, he wrote what many critics and fans consider to be Buffy’s superlative moment: an episode in which a central character died from natural causes, and which showed everyone else experiencing the shock, anger, and grief of her death in real time.

“The Body,” which aired on February 27, 2001, opened by repeating a scene that had concluded the previous episode. Buffy returns home, walking through her front door, commenting on some flowers sitting on the hall table, and calling out to her mother, who’s lying on the couch. When Buffy sees that her mother is motionless, she pauses, and her expression shifts. “Mom?” she says. She repeats the word, more urgently. Then, quieter: “Mommy?”

For Whedon, the episode was born out of a desire to explore and expose the real emotional responses to losing a loved one. On television, death is usually cheap: a device that precipitates a narrative arc, or writes out an actor who wants to leave, or functions as a ploy for ratings. Although some of these factors were involved in “The Body”—the death of Buffy’s mother, Joyce (Kristine Sutherland) marked a turning point for Buffy’s maturity into adulthood—Whedon wanted to focus not on the pain and catharsis of grief, but on how surreal and physically strange it can be. “What I really wanted to capture,” he later explained in the DVD commentary, “was the extreme physicality, the extreme—the almost boredom of the very first few hours.”

The first 13 minutes of the episode are set entirely in Buffy’s home. There’s a flashback to Thanksgiving, and then a swift and jarring cut to the present, where Buffy notices her mother’s body, calls 911, attempts to administer CPR, and responds to the paramedics. Joyce’s body—clearly and noticeably dead from an audience perspective—is visibly jarring, shown in close-up to have a grey pallor and an expression of shock. The title of the episode captures the impact of the physical presence in the living room, and the strangeness of Joyce’s sudden metamorphosis from a living entity into a dead one. Buffy, noticing that Joyce’s skirt has hiked up around her waist during her attempts to administer CPR, pulls it down before the paramedics arrive, conveying how wrong and obscene her mother’s death seems.

The sheer weirdness of this transmogrification from Joyce to “the body” is a theme throughout the episode. “She’s cold,” Buffy tells the dispatcher on the phone. “The body is cold?” the woman asks. “My mom is cold,” Buffy responds. Later, when Giles (Anthony Stewart Head) arrives and attempts to revive Joyce, not knowing the paramedics have already declared her dead, Buffy shouts, “We’re not supposed to move the body!” before clamping a hand to her mouth in shock, horrified at the consequences of what she’s just said. Stylistically, too, Whedon employs directorial devices to convey the disorientation Buffy feels. When a paramedic talks to her, the camera focuses on his chest below his head, and when Buffy picks up the phone, the buttons seem huge and distorted in perspective. There’s no music throughout the episode, with the few sounds that can be heard (children playing, wind chimes) marking the contrast between Buffy’s absurd reality and the world outside.

The peculiarity of the rest of Sunnydale carrying on as usual while the world of Buffy and her friends has upended is echoed later, when Xander (Nicholas Brendon) double parks his car going to pick up Willow (Alyson Hannigan), and duly receives a parking ticket at the end of the scene. Buffy’s friends, meanwhile, represent different responses to grief. Xander is angry, raging at the doctors and punching a hole in the wall. Willow is panicky and indecisive, obsessing over small details like her outfit rather than confronting the real source of her pain. Tara (Amber Benson) is supportive and accepting, with it emerging later that she’s experienced this before. And Anya (Emma Caulfield), a former demon who only recently became human, communicates a childlike response to Joyce’s death, asking irritating questions repeatedly and mimicking the behavior she observes from others. (When she clasps Giles in an awkward bear hug, it’s one of the few elements of humor in the episode.) Her monologue, after being told it’s not OK to ask such blunt questions, is one of the most moving moments in “The Body”:

But I don’t understand! I don’t understand how all this happens. How we go through this. I mean, I knew her and then she’s—there’s just a body, and I don’t understand why she just can’t get back in it and not be dead anymore. It’s stupid. It’s mortal and stupid. And Xander’s crying and not talking, and I was having fruit punch, and I thought, Joyce will never have any more fruit punch, ever, and she’ll never have eggs, or yawn, or brush her hair, and no one will explain to me why!

But it’s the scenes with Dawn (Michelle Trachtenberg), Buffy’s younger sister, that put the episode in context with everything Buffy has done over the past four seasons. When Dawn first appears in the episode, she’s crying in a bathroom at school because a classmate has spread rumors that she self-harms, and everyone thinks she’s a freak. This moment of pain—real for Dawn, but also surmountable, since she soon wipes her eyes and walks out of the bathroom head held high—is  juxtaposed with Dawn’s reaction when Buffy tells her that their mother is dead. The scene is observed externally by the audience, through a glass wall, and most of the words are imperceptible. But Dawn’s reaction, as she breaks into sobs and physically crumples to the ground, is unmistakable. Buffy, who’s spent the first half of the episode in vivid close-up, is seen from a distance, too, shifting roles from suffering impossibly to comforting her sister.

In this scene, Buffy draws an intriguing line. Throughout previous episodes, the show has told viewers that their experiences and their heartbreaks growing up have been real and powerful, from being bullied to being dumped. “The Body” manages to communicate, though, that there are a few certain life moments that change you irrevocably, and it does so without undermining the significance of other things that feel life-shattering in the moment. It presents a realistic experience of grief, reaching out to viewers who’ve endured it, and making it more comprehensible for those who haven’t. In tackling the less familiar aspects of death—boredom, shock, awkwardness—it offers a more truthful depiction of bereavement.

“The Body” is one of the most sophisticated analyses of the impact of death ever produced on television, and it remains a testament to why Buffy was so unique. “There’s things,” Tara tells Buffy about her own mother dying when she was 17. “Thoughts and reactions I had that I couldn’t understand. Or even try to explain to anybody else.” The power of Buffy is that it understands those thoughts, and does try to explain them, all in the guise of being a teen drama about vampires.