>She lives a double life completely hidden from everyone else
>She routinely looks for and stalks girls that bear even the slightest resemblance to Rose Quartz
>She eventually confronts them, flirts with them and sometimes manages to date them amongst other things
>When they stop meeting her standards or they refuse her advances, she kills them and disposes of their corpses at the galaxy warp
>She's been doing this ever since Rose started a serious relationship with Greg
>This is why Mystery Girl has never reappeared
>The only reason she hasn't done it to Steven is because he's a boy

holy shit
why does this work so well?