Yandere underfell mob sans x chubby singer reader

You are an undercover singer.
You sing backstage, you're voice heard, but unknown.
You aren't the singer, sure, you can sing..but Frisk? Frisk is the true star, the true show stopper.
You are just in the background, like you've always been, until a certain skeleton notices you.

Now, you've caught the attention of the infamous mobster, Big Papa, and he will do anything to make you his song bird. Anything.