Over the years, Buffy the Vampire Slayer has become the litmus test for feminist drama. But creator Joss Whedon didn't just turn gender roles on their head with his spunky vampire slayer. He flipped, remixed and defied all television conventions, preferring to play with the medium in novel and unexpected ways. While the Season 6 musical episode "Once More with Feeling" might be the most talked-about example of this, "Hush" is arguably the most eloquent.

Sandwiched in the middle of Season 4, "Hush," which aired Dec. 14, 1999, took away the thing that Buffy had become most famous for -- the snappy, witty dialogue -- forcing the episode to rely solely on musical cues and pantomime to tell the story of yet another murderous monster rampage in Sunnydale.

In honor of the 15th anniversary of "Hush," TVGuide.com spoke to some of the cast and the episode's composer about what goes into making a silent episode, creating the series' most frightening monsters and why Buffy never managed to get that Emmy.

Though Buffy would become known for its experimental episodes -- the music-free "The Body," the dream sequence-heavy "Restless"-- "Hush" was the first time the series took such a huge narrative risk.

ANTHONY STEWART HEAD, GILES: Every now and again Joss would come up with an idea. He'd have a little wry smile and he'd say, "OK, guys. We have one coming up and I'm going to direct it and it goes like this..."

CHRISTOPHE BECK, COMPOSER: I remember it might have been a Christmas party or something ... And Joss came and said, "Hey, we got this idea for a show in a couple months. Just wanna get you ready because it's going to be a bear." So when he told me more about it, of course it's an amazing opportunity for a composer but it's also, I mean, with TV music the deadlines are pretty crazy. ... So it was a little terrifying for sure.

DOUG JONES, LEAD GENTLEMEN: As I remember, I heard the network was kind of skittish to accept this. You know, you're going to have an hour of television with over half that hour in complete silence, which is taking one of the sensory buttons away. So they're thinking, "Capture your audience. Keep them from flipping the channel. Inundate them with visual and audio stimulation so they don't leave us." When you take the audio away, it's like, "Oh, dear!" So they thought it might be a gamble, but it turned out it's quite the opposite.

Do supernatural shows need a human element?

AMBER BENSON, TARA: I didn't [know] actually. It was kind of a surprise. Once I booked it, it was like, "Oh, by the way, half of this is totally silent."

HEAD: Joss' scripts were always something that you'd look forward to getting. And the fact that this came through not as a script, but as a beat sheet -- because of course there was no script initially. He just ran through the ideas that basically broke down into the beats of the episode, which is unheard of.

BENSON: It was awesome because I'm not the kind of actor who likes to go, "Oh, I have so many lines! This is awesome." I'm the actor that goes, "Oh, I have the least amount of stuff to do. This is awesome." So I didn't have to say anything. It was really wonderful. I just got to emote.

HEAD: [Whedon] tried it before, where he basically said, "OK, you're all in the library. I'm going to give you the chance to improvise because I'm not going to script this moment." And we were all useless. Useless! To the point where we were in the auditorium and I'm doing the slideshow and that was all scripted because he said, "I was thinking of you improvising this and you were so useless before that I've actually got to script the questions and basically I've got to write out every move and every moment in that scene because you can't improvise it."

BENSON: He knew exactly what was going to happen down to doors opening and facial expressions and movement. It was very, very thorough always.

BECK: It was five days and nights. It was a lot of sleep deprivation to get this done. ... Even though it was physically and technically a little torturous, I was into it from beginning to end. There was also the feeling that among the crew, especially the post-production crew, that we were making something special here.

BENSON: The music does such a nice job of setting the tone. It's very evocative. And the performances are wonderful. And the way it's put together, it's really smart. You start with a little bit of reality and then you juxtapose that with that silent stuff and it's really unsettling.

BECK: From the beginning, Joss was into the idea of a dark fairy tale, a twisted fairy tale. So you've got a lot of angelic voices and bells and glockenspiels that gives it the tinkling fairy tale sound. But at its core, and there are plenty of moments that go all the way with the idea of something darker and more horror based, but there's always an undercurrent there of darkness to go along with the fairy tale.

In the episode, a group of fairy tale ghouls, the Gentlemen, arrive in Sunnydale to collect seven hearts. As they conduct their business, they steal everyone's voices leaving them unable to call out for help.

HEAD: Initially, I must admit, I didn't quite get it. I got the Gentleman, but I didn't get the -- what are they called? I don't remember, the loonies that followed them. Well, the bottom line is the initial description was the Gentlemen would hover and go through the streets and they were followed by these people with straightjackets on. And I thought, "Oh, no, over-egging that Joss. I just think it was one step too many." Little did I know, because I didn't see any of the filming, so when I finally saw it cut together I was blown away. It was genius!

JONES: They do our groundwork for us. Literally. Because we float above the ground, as you're aware, were about 6 inches off the ground. ... If you saw us from head-to-toe floating above the ground, it's because we were in a harness underneath our clothes with wires that came out in the shoulder area all the way up to a key bar that we were sliding along a track. ... If you saw us from the waist up or a close-up shot kind of floating into frame or floating out of frame that means we were standing on a platform with wheels on it that some poor crew guy had to push us around on the floor. Bless his heart. It was not easy.

BENSON: Walking on set and seeing those guys, I mean, that makeup was so frightening on camera. It was even more frightening in person.

JONES: It was about four hours if I remember correctly. ... There's a mold maker that has to take a life cast of us and then there's the foam runners and the painters that actually pre-paint the pieces in the shop and then they go to the set and that's where makeup artist Todd McIntosh would apply it to me. ... So there was a different person for each department that would make them, apply them. They had a contact lens tech on set that would just take care of my eyes.

Sarah Michelle Gellar's Watchlist: What is Buffy watching?

BENSON: Doug and [fellow Gentlemen Camden Toy] -- those guys are amazing. They do so much with so little. Their physicality, just the way they move, the way they hold themselves. They're just really, really talented. I would say they're like silent film stars. ... So you get those guys that can do that. You put the makeup on them and they just move their hand and you're like, "I don't want to be near you. You're scary."

HEAD: Because they're mimes. Because they don't say anything and they smile. Interestingly we are the only animal that greets another animal staring full in the eye and showing our teeth. And there is something about a smiling villain that is really creepy.

JONES: A little known fact about those masks is that the original design for the mask was the smile was originally built into the mask. ... It was [Whedon's] instruction that the creature effects shop were to reformat masks for Camden and I to use our own mouths. That's why we had dentures put in our mouths. ... But that required us to put on a huge overdone smile all day long for every take. You know when you're at a party and you're going "hahaha" and all of the sudden your face starts hurting? Think of that, but for 12 hours at a time.

Despite the dark subject matter, "Hush" also took advantage of the silence to incorporate several visual gags as the Sunnydale citizens struggled to communicate.

HEAD: That's why Joss was and is still so clever. People didn't used to do comedy with horror. It was unheard of. It had to be schlocky. And I don't know, it's one of those things that he does apparently without thinking.

BECK: That is, of course, the challenge of a show like Buffy, which has so many of both [dramatic and comedic] moments. Generally on Buffy, I think this was true for "Hush" as well, especially when we're talking about a brief comedic interlude or moment inside of a much more dramatic scene, I try to stay out of the way. ... However, in particular, I remember the first scene in "Hush," as everyone's waking up and discovering they can't speak, it's very humorous. I remember in particular Xander picking up the phone before realizing that's a horrible idea and it's kind of a montage of these, what really is a pretty comedic sequence of everybody getting up and dealing with their inability to speak in different ways. And so that's an opportunity to do a one or one and a half minute piece that is overtly more comedic. I never quite get into what you might call cartoon-y or childish type of comedy. It always has a bit of a dark and twisted undercurrent, but there's definitely some pizzicatos going there.

HEAD: My daughter Daisy was saying she remembers it was one of the episodes, pretty much the only episode, that she wasn't allowed to watch. [My kids] were 5 and 7 I think, or maybe 7 or 9. And I thought it might be too scary for them. ... "Hush" was truly scary. So the moment that the slideshow scene was just a nice moment of light relief. It's just brilliant that it's a bunch of people not being able to talk all trying to pitch in and have ideas and there's some great gags. I can't remember. Nick [Brendon], he has some inappropriate comment and it's just very much out characters come through. And it's funny. ... It was one of those moments where we were an ensemble at our fullest. And that much was great fun. When we had those ensemble moments and they really worked, it was so good.

HEAD: She was very shy, much like Tara. And I remember she came on set with her mom.

BENSON: You know, I wasn't sure what the deal was, if it was just going to be one episode or just a couple of episodes. So I sort of treated it the same way I treated any guest spot that I was going to do. Sort of go in and you want to put your best foot forward and you want to enjoy stepping into a world that's already created, but you also don't want to step on any toes.

HEAD: Well, originally Oz (Seth Green) was going to be around a lot longer. And I can't remember what happened, but I think Seth had another gig. Something happened where basically Joss had to rethink and as with all great things with Joss, he came up with the idea of Willow finding a female lover.

BENSON: It was funny though. The rest of the crew picked up on it immediately. They're like, "You guys have such chemistry." And we're like, "Wait. What?"

The best TV shows of 2014

HEAD: Being able to go down that whole route which had never really been touched on in mainstream TV. It has since, but at the time in the '90s I remember. There's a friend of ours who was a policeman who at the time said his daughter, she was about 14 or something, "We got to the Willow and Tara bit. We're having to edit out our response." And I said, "What are you talking about? This is a golden opportunity for her to ask all the questions that might be going on in her mind and you to answer them! Don't edit them for god sakes!" Joss gave so many people means of self-expression to ask the questions that they needed to ask and also have answers for them without even asking them questions sometime. It's alright if you're gay. You don't have to apologize. It's part of life. It's part of growing up, part of being.

BENSON: At the time, we were just like doing witchy stuff, but when you look back you're like, "Oh, this was in the stars. This was meant to be." And I think Joss had always in his mind known that was the way it was going to go. He just didn't tell anybody.

Throughout Buffy's seven-season run, "Hush" was the only episode to score a major Emmy nomination when Whedon was recognized for Outstanding Writing for a Drama Series (he ultimately lost to The West Wing). However, Beck's score failed to earn him a nod, though he had previously won for the Season 2 Episode "Becoming Part 1."

BECK: The episodes are chosen by me at the end of the season to submit for Emmy consideration and that happened to be what I thought was strongest musically. And to not get a nomination for "Hush," and I have to admit -- I guess I can admit this stuff 15 years later -- I'm a little surprised.

BENSON: You know, I think when you're dealing with genre television, there's a bit of a prejudice against it. "Oh it's genre. It's not worthy of being recognized." It's not a drama or a sitcom comedy. It defies classification. Buffy was smart. It was funny. It was irreverent. It was absurd. And it was terrifying and it was heart wrenching. It was all these different things at once and people don't quite know what to do with it. So that's why I think it sort of got snubbed every year. It's really a shame.

HEAD: Insane. Absolutely insane. And I think there was always something that got in the way. Either Fox or Warner Bros. didn't have copies to give to the committee or honestly stuff just got in the way. Throughout the seven years, I thought someone somewhere along the line is going to work out that this is really good TV. And it just never ever got it.

BECK: I think it's very easy if you're not watching the show or if you're not a fan of the show to dismiss it as fluffy, as for girls, as on a network that nobody took seriously. So I think it had a lot of things working against it. But I do believe if the voting membership of the TV academy knew the show as well as all of us or fans of the show did, it would be a different story.

HEAD: Get your vote to the Emmys and say its time Buffy is recognized. It's such groundbreaking TV. And to only have had one nomination for writing and nothing else. Nothing else! And I remember they were supposed to put "Once More with Feeling" up for an Emmy, and I think Fox or Warner Bros. or somebody dropped the ball. They never got the copies for the committee to see. Insanity! Somebody must have been sabotaging this because that's ridiculous.