Buffy the Vampire Slayer was a show known for creative storytelling. Books have been published about it on everything from Scooby Gang slang to sexuality, media studies, and feminism. Buffy challenged what was possible or acceptable for television at the end of the millennium, pushing boundaries.

One of the most iconic and lauded episodes of Buffy the Vampire Slayer is “Once More, with Feeling,” the musical episode. Series creator Joss Whedon had been planning a musical since early in the series. In season 6, it finally came to pass.

According to Whedon, the inspiration for the episode came during a social gathering at his house. Anthony Stewart Head, who played Buffy’s stalwart mentor and father figure, Giles, began singing at one of these parties. He had great vocal skills and roped the rest of the group into joining in. Whedon realized that they had a trove of unused musical talent in the cast and decided to put it to use.

“Once More, with Feeling” seems to have come whole into Whedon’s mind. Before Season 6 started filming, he presented producer Gareth Davies with not only the entire script for the musical but also the sheet music and recordings of every song. This was the first time Whedon had written music.

Despite this clear vision, making a musical is an incredible amount of work, especially on a network television schedule where each episode needs to be filmed in about eight days. The actors had after-hours dance lessons and three months of vocal training, all while filming the rest of the season. This episode also included more complex technical choices, including several long takes and a widescreen letterbox format for filming.

“Once More, with Feeling” served a moment of much-needed levity in Season 6, one of the grimmest (and least liked) seasons of the series. Buffy the Vampire Slayer had always focused on themes of growing up, and Season 6 was no different, focusing on issues faced by many young adults — getting a job, paying the bills, dealing with romantic and platonic relationships, and handling conflict without leaning on or hiding behind parental figures.

Throughout the season, each character had been wrestling with these struggles internally, concealing them from the rest of the Scooby Gang. But when the demon Sweet (played by three-time Tony Award winner Hinton Battle) comes to Sunnydale and the town unwillingly bursts into song and dance, they are forced to express unspoken secrets in song.

“Normally in a musical, you want to burst into song. But in Sunnydale, it’s forced upon us, which causes even more chaos.” — James Marsters

Whedon used a variety of musical styles to play to the actors’ strengths and included dance numbers as well. One unexpected example of this was Willow’s girlfriend Tara, usually a quiet and reserved character. Alyson Hannigan, who played Willow, begged to sing as little as possible, but it turned out that Amber Benson, who played Tara, had a beautiful voice and was given a chance to take the lead in several critical songs. Michelle Trachtenberg, who is trained in ballet, performed a dance instead of a vocal solo.

There is no denying that this episode is silly, and it maintains a fun self-awareness throughout. Characters were frustrated with the incessant singing and dancing, and as Anya (Emma Caulfield Ford) cheekily says at one point, “It was like we were being watched. Like there was a wall missing from our apartment. Like there were only three walls and not a fourth one!” One of Willow’s few lyrics is, “I think this line is mostly filler.” When Buffy (Sarah Michelle Gellar) is up against Sweet (Hinton Battle), Giles sends her backup dancers.

As Anthony Head got his friends and coworkers to open up and sing, so does Whedon get his characters to break their silence and share their secrets. Although the episode ends in classic musical fashion — with a kiss — it is not a particularly happy ending because the reality is that sharing secrets is not enough. The characters still needed to take responsibility for their actions and act upon the epiphanies they made in this episode. It served as a critical turning point for the emotional arcs of every character for the season. Gellar was not keen on singing in the episode, but when someone suggested a voice-double she said:

“I basically started to cry and said, ‘You mean someone else is going to do my big emotional turning point for the season?’ In the end, it was an incredible experience and I’m glad I did it. And I never want to do it again.”

Some fans complain that the musical episode was too campy or that the actors’ voices were too unpolished. However, Buffy has always been incredibly earnest; it’s what many fans love about it. Decades later, “Once More, with Feeling” is one of the most memorable episodes of the entire series. The cast and crew threw their all into this episode, and the result is both profound and charming — what Buffy has always been best at.