Big Hero 6 type Movie genre Animated

The best part of Big Hero 6—the awesomely odd exploding-fist sound cuddly robot Baymax makes when bumping knuckles with his pal Hiro—comes as a delightful surprise for audiences…which is fitting, since it was initially received the same way by the guys who actually made the film. “I remember having that feeling of like, ‘That’s really weird and strange, and it’ll never make it into the movie,” says co-writer Robert Baird, who was listening when the voice of Baymax (30 Rock alum Scott Adsit) loosed his first “balalalalalala.”

Of course, there’s more to the story than that. It takes a village to make an animated movie—which is why EW chatted with four separate Big Hero crew members to get the full story behind the fist-bump. Click here for more of EW.com’s Best of 2014 coverage.

ROBERT BAIRD, co-writer: There’s this fantastic relationship in the movie between Hiro and Tadashi, and we were always looking for ways to make it seem authentic. [Disney Animation chief creative officer] John Lasseter, who’s the father of five boys, said, “Brothers are physical, and they push each other a lot, and they say a lot with just a slap or a fist bump.” And we thought, of course—when they accomplish something, let’s have them do one of those. Our story artists Marc Smith and John Ripa, they went off and came back and said, “Maybe it would go something like this.”

MARC SMITH, story lead: The idea got thrown out that it would be some sort of handshake. John and I were sitting kind of on the sidelines. We both have children around the same age; I think I was showing John one of the [handshakes] my kids had shown me. It’s called a Turkey. There’s another one, a Snail. John had a more involved one.

JOHN RIPA, story lead: I was showing Marc that on the side in this meeting, trying to figure out what [Hiro and Tadashi] could do.

SMITH: That one included the little fist-splosion thing that ended up in the movie. We looked over and Paul Briggs, our head of story, was filming us.

RIPA: Which we deeply regret. I remember thinking, “I hope that video doesn’t ever wind up anywhere.”

BAIRD: They worked out this elaborate fist bump; it was a way to show this great relationship between Hiro and Tadashi. As the story progresses and Hiro loses Tadashi, Baymax becomes a real sort of surrogate brother to Hiro. We said, we’ve set up this great fist bump—Hiro has to teach him how to do that fist bump.

My writing partner, Dan Gerson and I, wrote these pages where we said, “Hiro teaches the fist bump to Baymax, then does this exploding fist sound.” Then we wrote, “Baymax does his robot equivalent of whatever that exploding fist sound would be.” We had the brilliant Scott Adsit get into the booth and record that scene. When he got to the exploding fist bump sound, he gave us this whole variety of different sounds—exploding sounds and digital robot sounds. And then he did this weird “balalalala” sound. I remember everybody in the booth laughing, and thinking, “Well, we’ll never use that. That’s too weird.”

TIM MERTENS, editor: Rob and his partner Dan come up with the script, and they pass it off to the story artists, and then they board certain scenes together. They’re passed off to me in an editorial turnover. So I’ll get the material and basically cut together a scene, then play that for the directors and writers and so forth in order to get some feedback. It’s definitely a process that lends itself to change, and constantly trying different things. You never know what might land until you actually try it—à la their “balalalalalala.”

As I was going through the takes [of that scene], I happened upon this thing and I pretty much just burst out laughing. To watch this robot learn human traits—whether it was that “psssh” sound Tadashi and Hiro had shared or this sound, it was going to be a great scene. And so I tried this, and they played it in editorial one day, and everybody just busted up.

BAIRD: Tim cuts together this 90-minute movie that’s just storyboards, and we play it internally. They’re watching the movie, Baymax makes that sound—and the whole theater just erupted.

MERTENS: And it grew from there. We kept trying to find places throughout the film to let this sound, this balalalalala sound, land. And I think we picked just the right amount.

BAIRD: It was incredible. Every time he did that sound, people would erupt with even greater laughter.

SMITH: We watch these movies over and over and over and over, and that was one of the moments in the film that always got a laugh. People have seen it 10 times, and it still got a laugh.

BAIRD: It is the same recording each time. He is a robot, so he would repeat the same phrase.

MERTENS: Every time he says “Hello, I am Baymax, your personal healthcare companion,” it’s always the same take.

RIPA: We started to add it in other places and keep it as a running sort of joke, until it becomes more poignant in the end.

BAIRD: At the very end, after Hiro has lost Baymax, all that’s left is that fist in his lab. We realized we had a real opportunity—something turns from comedy into poignancy when he does that fist bump at the end with the Baymax fist. He makes that little sound, and suddenly people go from laughter to—it’s just this bittersweet moment. It was a really beautiful thing.

RIPA: We had just had a screening, and we were in a notes session with John Lasseter. In that screening, Hiro didn’t do that fist bump at the end. I said, “He should do that thing, the Baymax thing, balalalala.'” And I remember John Lasseter at the time, he’s like, “I have it right here!” It was in his notes; he’d written that same thing.

SMITH: The fist bump was one of many little ideas—there’s things like Hiro on the back of the scooter looking at the reflection of him and Tadashi, which echoes later on in the film with Hiro and Baymax when they’re flying around the big building and they look in the mirrors. There’s another one—in the beginning, when Hiro says he’s going to do another bot fight, Tadashi grabs Hiro by his hoodie. Later on when Hiro is following the microbots, he almost walks into the bay—but Baymax grabs him by the hoodie again. It’s a very similar gesture. That was intentional.

RIPA: We try to find many little subtle moments [that make] you feel like Baymax is becoming a surrogate brother to Hiro.

MERTENS: It was interesting watching the movie in theaters after its release, because audiences sort of came to expect that sound. You can sense the audience anticipating a balalalala. I don’t think we could have spoon fed them enough of that.

BAIRD: I was out with my son playing Little League, and I was watching some other kids. They made a great play, and they ran up to each other, and I saw them do the fist bump and the balalalala. It almost made me cry.