“Better Than Mark Ruffalo”: Inside the Wild, Joyful Finale of Teenage Mutant Ninja Turtles: Mutant Mayhem

“One little horse? I don’t need that horse.”

According to Seth Rogen, the punchline that deflates a climactic scene near the end of TMNT: Mutant Mayhem was improvised in a recording booth by Ice Cube, who was told to imagine what a giant mutant built of animals might say while stomping around Manhattan. It’s not the kind of thing any actor might easily conjure on their own—and for a long time in the film’s development, the mutant was only supposed to roar, not talk. But at some point, Rogen says, “We were like, ‘What if it’s this big monster, but it still sounds like Ice Cube?’”

That kind of story development—what if this crazy thing happened?—becomes a major part of Mutant Mayhem lore when you talk to Rogen and Jeff Rowe, the film’s director, who guided the movie through one story revision after another on its way to becoming one of 2023’s most pleasant surprises. A Ninja Turtles project with a big emphasis on the “teenage” part, it’s got the sweet awkwardness of Rogen and Evan Goldberg’s Superbad, which they reference often when talking about Mutant Mayhem. But it’s also an inventively, endlessly funny action film, culminating in a kaiju battle in the streets of New York that makes time for character development for all four turtles; a heroic news broadcast for their pal April O’Neill; and a group of New Yorkers banding together in what Rogen freely calls their “Spider-Man 2 moment.” Here’s how they made it happen.

They Have a Goal, Just Not the Right Goal

Throughout Mutant Mayhem, our teenage heroes Leo, Donnie, Raph, and Mikey have just wanted to be accepted by human society. They’ve determined that bringing down the villainous Superfly (Ice Cube) and his own family of mutants is the way to do it. But their efforts only create a big, scarier version of Superfly who then rampages through New York City. As the film’s action climax begins, the turtles are marching into Manhattan with a weapon they think can solve the whole thing and get humans to accept them at last. At the same time, their adoptive father Splinter (Jackie Chan) has realized he has to let his kids march into danger—but hasn’t yet come around to stop fearing humans. Everyone, it turns out, still has something to learn.

“It’s something I’m always reaching for, and I actually think we did it well in that moment—the audience feels as though you’re giving them the answer, but it’s actually an incomplete answer,” says Rogen. When this approach works well, he says, the audience gets the thrill of an even better solution being revealed right alongside the characters. “There’s high standards for animated movies these days,” Rogen says. “There was a very conscious effort to have the third act continue to deliver this kind of emotional catharsis. It’s nice, I think, for the audience to go on that journey too.”

They Had a Monster, Just Not the Right Monster

Like many animated movies, Mutant Mayhem’s story transformed dramatically throughout its production. They got far along in the process with a big third-act monster who was not Superfly at all: At one point, the foe was created by Shredder, the iconic Turtles villain who now only appears in a brief hint at the end of the film. Though the story part of it wasn’t working, the animation had begun. As Rowe puts it, “We had already started building it, and it was a big, expensive, complicated asset…. And then at some point, Seth was like, ‘Wouldn’t it make more sense—instead of Superfly creating a monster, he just becomes the monster?’”

The result, Rowe says, was a 48-hour dash to turn the pre-existing monster—a jumble of animals that formed a vaguely Godzilla-esque shape—into something that conceivably could have once been the mutant insect Superfly. “It was like, ‘Can we put fly wings and fly eyes on this giant whale monster?’” Rowe remembers. “When we did that, the story clicked into place. But if we hadn’t already sunk a lot of time and energy into that asset, we may have had a different ending to the film.”