The movie is called Reptile because as each character is introduced, their nature changes, and after appearing to be one thing, they soon "shed their skin" and are revealed to be something else.
The photo of the 1990 Red Buick LeSabre shown to Nichols was actually the result from an internet search. The photo was taken in 2007 and is public domain. If you google 1990 Red Buick LeSabre you'll find the exact same photo used in the film.
Grant Singer's feature film directorial debut. Singer has directed several music video and one documentary film, Shawn Mendes: In Wonder (2020), but Reptile (2023) is the first narrative film that he has directed.