Thomas Cailley cut a 2 minutes epilogue between the film's screening at the Cannes film festival and its official release.
According to him, "in the end [he] felt like it was more interesting not to answer all the questions that the epilogue answered. To leave them open."
Filming ended one month after schedule due to a forest fire that destroyed the film's settings in August 2022.
Two years before the shoot, Thomas Cailley worked for six months with comic book artist Frederik Peeters to design a slate of creatures: mammals, birds, arthropods, etc. The resulting designs were then used as the basis for character designers specialized in morphology to finalize the look of the creatures. Cailley looked at works from artists Patricia Piccinini and Ron Mueck to find inspiration, as he didn't want to end up with something common, like the overused virilist figures used in video games or heroic fantasy in general.
The idea for the movie came from a script written by Pauline Munier, while she was still a student at the Fémis film school. Thomas Cailley, who was selected to assess the student's scripts, loved the idea of humans slowly mutating into animals, and offered her to write a feature length movie based on her script.
It was selected as the opening film of the Un Certain Regard section at the 2023 Cannes Film Festival and had its world premier there.