Rebecca Sugar stated that what she wanted people to take away from the movie and Spinel's character arc was that it's alright to be a 'work in progress' and it's you who needs to want to change and get better.
Rebecca Sugar based Spinel on a favorite stuffed rabbit that she once carelessly abandoned in her backyard as a child. Upon rediscovering it six months later, she found the toy had permanently changed after exposure to the elements. This same incident also inspired the 'Everything Stays' segment in Adventure Time.
Pink Diamond and Spinel are the only two gems to have been seen rotating their gem when taking a new form.
Spinel is a throwback to early 20's/30's cartoons, in her appearance, mannerisms, and her opening musical number.
Spinel's transformation back to her alter form is similar to a magical girl transformation, taking inspiration from the transformations seen in Sailor Moon, an anime that Rebecca Sugar has made references to in the show.