The Anomalous Rose (Male Neglected Gaster Reader x RWBY x Multiverse)

The Rose / Xiao Long family is a 'happy' and 'perfect' family consisting of 2 parents and 🗏︎ 2 children. However, a certain boy, crow and raven know otherwise, even the 2 children of said family are aware of the problem.
One day, within the ̶♒̶︎̶♏̶︎̶●̶︎̶●̶︎̶♒̶︎̶□̶︎̶●̶︎̶♏̶︎̶ paradise, a boy is greeted by the strangest visitor.

⚐︎■︎♏︎ ♎︎♋︎⍓︎📪︎ ⬥︎♓︎⧫︎♒︎♓︎■︎ ⧫︎♒︎♏︎ ♒︎♏︎●︎●︎♒︎□︎●︎♏︎📪︎ ♋︎ ♌︎□︎⍓︎ ◆︎■︎●︎□︎♍︎🙵⬧︎ ♒︎♓︎⬧︎ ⬧︎♏︎❍︎♌︎●︎♋︎■︎♍︎♏︎ ♋︎■︎♎︎ ♋︎●︎●︎ ◻︎♒︎⍓︎⬧︎♓︎♍︎♋︎●︎ ♏︎❖︎♓︎♎︎♏︎■︎♍︎♏︎ □︎♐︎ ♒︎♓︎⬧︎ ♏︎⌧︎♓︎⬧︎⧫︎♏︎■︎♍︎♏︎ ❖︎♋︎■︎♓︎⬧︎♒︎📬︎ ❄︎♒︎♏︎ □︎■︎●︎⍓︎ ⧫︎♒︎♓︎■︎♑︎⬧︎ ●︎♏︎♐︎⧫︎ ♋︎❒︎♏︎ ⧫︎♒︎♏︎ ⬧︎♍︎❒︎♋︎◻︎⬧︎ □︎♐︎ ❍︎♏︎❍︎□︎❒︎♓︎♏︎⬧︎ ♋︎■︎♎︎ ♋︎ ♍︎□︎■︎⬧︎⧫︎♋︎■︎⧫︎ ♐︎♏︎♏︎●︎♓︎■︎♑︎ □︎♐︎ ♑︎◆︎♓︎●︎⧫︎ ♍︎□︎■︎⧫︎♋︎♓︎■︎♏︎♎︎ ⬥︎♓︎⧫︎♒︎♓︎■︎ ⧫︎♒︎♏︎ □︎■︎●︎⍓︎ ◻︎♏︎□︎◻︎●︎♏︎ ⬥︎♒︎□︎ 🙵■︎□︎⬥︎ ♒︎♓︎❍︎📬︎

I do not own RWBY, Undertale or any anime / game / etc universe I include in this fanfiction.
I do not own any images or videos included in this fanfiction.
This is also my first story, so don't expect anything good. I hope you enjoy.
Oh, also I am extremely lazy so expect extremely slow updates.