Sour is an original character, or OC, made by a fan for the Sprunki community rather than an official Incredibox character. Sprunki itself grew out of fan-made music-mixing games inspired by Incredibox, where each character contributes a loop to a shared beat. In that format, a normal mode sound is the character's everyday version, distinct from the darker horror mode used in many fan mixes. Creators share these OC sounds in mixes, showcases and edits, keeping Sour useful as a recognisable voice for fans building their own Sprunki line-ups.