THIS is just a random character design for a background character.
a tune that ended up killing a person in self defense. she thinks she's a bad person for that so naturally she became a thug
tunes that look like they're based on animals aren't actually related to them. the way tunes are made are generally uninformed "interpretations" of what humans might perceive to be charismatic or funny. to put it extremely loosely. so ones that look like cartoon characters, for example, which people watch every day... would definitely show up
this one ended up looking like some kind of. bug eyed. rat weasel.