It is based on the short film 'Rabbit' by the same director. In this short, a prisoner is entrusted to this animal as part of the "pet association" program of the prison.In one scene, Coleman's cellmate sarcastically refers to him as John Wayne. Bruce Dern, who appears in this film, appeared alongside Wayne in The Cowboys, murdering his character. It was one of Wayne's few on-screen deaths.Laure de Clermont-Tonnerre's feature film directorial debut. She developed Mustang through the Sundance Labs and received the Sundance Institute/NHK Award for the project in 2015.