Concept art for Capper dated October 2015 in the art book The Art of My Little Pony: The Movie shows him going through various design iterations, including a black-footed ferret, a Siberian Husky, and a honey badger. According to the film's art director Rebecca Dart, Capper was originally going to be an anthropomorphic fox with a scorpion tail named "Mendax" (the Latin word for "liar"). Concept art dated March 7, 2016 shows that he was also called "Tybalt" at one point.