As a feature film writer and director, Brad Bird has been responsible for some of the biggest box office successes of the past 15 years. For Pixar, he directed both The Incredibles (2004) and Ratatouille (2007). For Paramount, he engineered a fourth entry in the Mission: Impossible franchise, 2011’s Ghost Protocol.

But there’s one film that’s been gestating for over 20 years that, despite Bird’s enthusiasm, hasn’t gotten off the ground: an animated sci-fi noir titled Ray Gunn.

Concept art by Sylvain Despretz. film ick

The project was conceived in the early 1990s with co-writer Matthew Robbins. Intended to be a 2D animated film for Turner Entertainment, Ray Gunn tells the story of the last human private detective hired to investigate the alleged infidelity of a pop singer named Venus Envy. Navigating a world coinhabited by humans and aliens, Gunn finds that Envy is being set up by her scheming husband to take the fall for the murder of her body double.

Trade papers described it as a cross between Raymond Chandler and Buck Rogers, with Bird aiming for a futuristic setting depicted as though it had been designed in the pulp novel heyday of the 1930s. Bird once said the idea had come from mashing together a B-52's single, “Planet Claire,” with elements of the 1950s TV detective show Peter Gunn.

But Bird—who was a creative consultant on The Simpsons—couldn’t sway Turner executives into giving him a green light. He had even less success with Warner Bros., which merged with Turner in 1995 and displayed no interest at all. The reason? The studio believed it might have been too intense for younger viewers.

Concept art by Sylvain Despretz. film ick

“I see it as being very mainstream, but Hollywood saw it as being almost experimental, like, ‘Whoa, what the heck is this?’” Bird told Ain’t It Cool News in 1999. “In animation, you're always fighting against, ‘Well, that might upset a 5-year-old.’ My feeling is, ‘Well, then, the 5-year-old shouldn't go. Come on, can't we make some other things?’”

Gunn, said Bird, had gotten a bit of a reputation as more of an adult-themed project than it really was. “Everybody was going around saying it was R-rated and Pulp Fiction, and while there's nothing wrong with that idea—I'd certainly be interested in seeing a film like that—it was PG, you know? Maybe PG-13.”

Despite being completely storyboarded and scripted, Ray Gunn was shelved when Warner convinced Bird to focus his efforts on 1999’s The Iron Giant, based on Ted Hughes' 1968 book, The Iron Man. That work led him to Pixar, where he backed some of the studio’s biggest hits. No other studio has come forward with interest in reviving the project.

Having most recently directed 2015’s Tomorrowland, Bird hasn’t given up on Ray Gunn completely. He recently reiterated his desire to return to 2D animation and said he remains “enthusiastic” about the premise. “There’s a sense of wonder very specific to me about hand-drawn animation,” he told the Bancroft Brothers Animation Podcast in 2015. “I miss that.”