Curiosity Killed the Cat {Undertale Au Fanfic}

Curiosity is a rather...fragile... thing. It can fuel creativity and inspiration, yet it can also lead to harms way. After all, curiosity killed the cat, right? But when one being becomes let's say...too curious... with said curiosity being fueled by a rather twisted personality, what happens when this leads to a dangerous curiosity to which could impact the multiverse for who knows how long and for who knows what way? What if said curiosity leads to a form of...experimentation?... When combined with such a dangerous curiosity, what if a certain Guardian of Positivity is particularly desperate to get back someone he had lost? Desperate enough that he may be willing to try...anything?

{Knowing my story writing tendencies, I'm just going to go ahead and put a possible trigger warning for Blood, Gore, Experimentation, Death, Swear Words, Depression, Manipulation, and Violence.}