Yandere!Gaster X Reader: My Beautiful Experiment

chapter two: Awake part 1

Papyrus was overjoyed and eager to find out about this new 'friend' of his, "Who are you? I'm Papyrus! And the other one is my brother Sans! Say hi Sans!" But Sans was a bit apprehensive, could this be some kind of trick or something? "Uh yeah hi," Sans said a bit lazily, compared to paps that is. "How come we've never heard you before," he said with a shrug even though she couldn't see, "If ya don't mind me asking." Paps didn't want to say it but he was curious as well though he would've worded it much more differently. Y/n stayed silent for a moment causing papyrus to worry if she would ignore then now and not want to be their friend. Then Y/n spoke up, "Well I think I just woke up but I don't know for sure all I remember is sitting in a room with queen tories, King asgore and my friend asriel"

This confused them there was no Queen Toriel not anymore at least and asriel had been dead for 13 years She was met with an ungodly silence as they wondered how to break this to her. But before they had time or any of them could speak a door was heard opening down the hallway. the two skeleton brothers knew it well and they could only think, 'No no no no no.' "Who is that," she asked not knowing to be quiet when such door opened. Being awake meant tests. And more tests meant pain. They were frantic speaking a language silently, well she could still hear them, but didn't know what it was. The two were discussing what to do with her. How to help her and blubbering about how they didn't want more tests. They spoke in the windings to each other or whenever they speak to their father, "San what if he finds out ab-" Papyrus was cut off by gaster opening the door to their room. "Hello my sons." Sans growled, "like I'd ever think of you as my dad your just a freak who's obsessed with this 'Y/N' person. Who are they dad?! Another of your presious children made to be put through hell!" Sans yelled at his father. His voice full of hatred and betrayal. Gaster was confused, why were they speaking about Y/N all of a sudden when they had never asked before? 'But that could only mean. . . ,' he thought his eyes widening as he dropped his clipboard in shock. He wasn't even aware at the creepy smirk that settled on his face, "So she has awoken has she?" He couldn't help but wonder how they knew but walked out anyway eager to see his newly awakened test subject. After he left Sans and Papyrus shouted at her to pretend she was asleep. She was confused as to why they asked her to do that, but did so anyway as she even made it look like she was limp to make it convincing. 'Was this finally happening at last after all or. . ?' He walked up to the test tube, tapping on her glass like coffin chamber he had designed for her. Trying to find the slightest hint of a flinch. A movement of the eyelids. Shifting of breathing. Something! Anything!! But was met with nothing, but had he not have turned away in disgust he would've seen a movement of hair. Meaning she would have been awake and he had been right, but as far as he knew. . nothing. How dare they give him hope?! He wasn't sure why this angered him so much, I mean, she IS just a test subject. It's not like he's . . attached or anything. He spent a totally normal amount of time on her tests just like the others. . Yes that's right the others. . But he had no time for that now. He was being called to the castle to check up on the king for his normal checkup. Gaster quickly left the room and went to the castle slamming the door in the process causing Y/n to flinch before she opened her eyes 'nothing'

"Sans? Papy you guys there," Y/n questioned, "can you guys tell me my you went quite when I mentioned toriel and asriel and why I had to pretend I was asleep?" There was such an innocent tone in her voice that they considered if they should really brake her spirit like this. It wasn't like she didn't deserve to know and she couldn't really pretend to sleep forever, they were pretty sure Gaster had performed tests on her while she slept. There was no way she could fake it through that, so they decided to tell her the truth in a gentle manner, and she had to take it all in. Gaster's experiments on his sons and possibly her now as well. Toriel and Asgore breaking up. Her brother's death. Had it been her fault? She couldn't remember. She knew of Asgore, Tori and Asriel but anything else besides her goat family was a blur. Including how she came to this place. "S-so..I'm all alone now..is it my fault and you guys...his sons and he did that..?" Y/n asked as she slid down the glass. Her head in her knees as she started to cry. Papyrus even started to cry, "P-please don't cry it isn't your fault you have to stay determined I know someday we'll get out and when we do you'll come with us! Right Sans?" Papyrus stared at Sans begging him to let her tag along with the plan. Sans couldn't very well in good conscience leave someone who reminded him so much of Paps and him when they started out in this place. And no one deserves to be left to suffer like they did. "Sure Paps. We'll bust Y/n out for sure," he said patting his bro's shoulder, "like hell we'd leave her with that creep. You could say. . " Papyrus immediately stopped crying and glared at his brother, "Sans!" "I really. . ," he continued to press on with a wide grin at his annoyed brother's face.

"Sans! Don't you dare," Papyrus warned him, irritation clearly in his tone. Making Y/n wonder what he could say that was so bad, and part of her wanted to hear it out of curiosity. "Feel it in my bones~," Sans finished, clearly proud of himself while Papyrus groaned. "Whyyyy," he groaned comically. They were met with silence from Y/n before she burst out into a fit of giggles laughing. They were surprised. It's the first REAL laugh they heard in that godforsaken place. Where everything was determined. . and freedom meant nothing "Hehehe t-that heh was good," Y/n said as she dried her tears, "when we get out of here you should be a stand up comedian that is if you don't get tired and have to sit down." Y/n laughed a bit, "I'm sorry I'm quite rusty with puns as I seemed to have sleep for a while." "Speaking of that what year is it," Y/n asked. Sans chuckled at her humor, happy to be in good company. "Nothing wrong with it," he said smirking casually as his brother moaned about how he "corrupted the human". "I found it pretty humorous tibia honest with you," he finished with a wink despite two facts. One she couldn't see it. And two he was a skeleton so how the hell was he winking?! . . . The world may never know. but Papyrus wasn't as happy as his brother was so Sans decided to stop for his sake. But neither of them knew what year it was. They had been down there for so long time meant nothing, but they knew as much as 13 years since the incident. And they told her that. They were really sorry they couldn't tell her anything else. Y/n nodded even if they couldn't see "Ah that is alright I'm just glad that I have someone I can talk to," Y/n stopped for a moment, "wait does that mean it was just you two? And no one else to talk too?" Y/n couldn't even begin to imagine how horrible their lives were even if she was was here now they still had years of torture and by their own father too. "I'm sorry about that. . . ," Y/n muttered. They both smiled at that. This girl had cared about them in just the few minutes she had met them. In fact Sans chuckled quietly to himself bitterly, 'How messed up is it that a stranger can give you more love and understanding than your own family can in years? Heh heh this world is messed up but. . ' Now he was determined to get his bro and Y/n out of here. No matter what.

As Y/n was about to say something else a click if a door alerted them and Y/n knocked lightly on the glass to alert them she was going to fake being asleep again and went back into her 'sleep' mode The brother's sighed in relief as she had usen the code they had agreed upon. Knowing she was safe and 'asleep' meant something to them, but they knew being 'asleep' wouldn't last her for long if they knew Gaster. Gaster wasn't above experimenting on sleeping patients they've woken many a time to being strapped down or with something new in them. Sans hated his Dad, he didn't know how Papyrus still believed in the good in him. Sure he loved how his innocent little brother could be determined, but there wasn't any good in that guy. Gaster took one look at Y/n 'still asleep' that didn't answer his question about how sans knew about Y/n it had been distracting him all day perhaps if he didn't experiment on them until after dinner. Gaster walked by Y/n but she stayed asleep but was about to open her eyes until she heard him again and closed them again quickly. He thought he had caught movement from his subject, but quickly shook it off as him being . . hopeful? Why did he care again? It didn't make sense. Maybe because she was important to Asgore? And Asgore was an old friend of his, so maybe that was it? . . No! What was this feeling, or the need to constantly check on her after every experiment? look at he slowly breathing form? What was it that was so important? Her soul maybe? No that's not it! What was it?! being so frustrated he hadn't realized he had hit the top of her glass lid with his fist, causing a tiny hairline fracture in it. "Ergh. Yet another thing I have to fix," he grumbled before stalking out of the room, but not before casting her one last glance. Running his skeletal fingers over the glass. Once he finally left y/n shook and let out a sigh, 'that was close too close'

Gaster walked to his sons room with some pasta for papyrus and some grillbys fries and burger for sans, "Kids? Can I come in?" Sans rolled his eyes, 'since when did you care if you can or can't come in?' Sans felt his eye flash painfully, after Gaster's last experiment he's been doing that lately and it terrified him. And he couldn't figure out why! Before either of the two could answer Gaster came in anyway, meekly offering the food as if it would make what he's done any better. He pulled Papyrus behind him, even if the younger one was waving meekly at him with a smile. He didn't know why his brother did that everytime, waving at him like they were FRIENDS. Or a goshforsaken family?! Gaster eyed the two before letting out a sigh, placing the food on the floor sicne there was no table. he sat in a chair he had provided for himself when he came to talk here. "So. . . How are you feeling," he asked, it would be a normal question for a normal family if he were a "normal" father. He meant the experiment and if anything "interesting" as he liked to call it was happening.

​​​​​​(All chapters from here are made in CO with animemaiden :3 everyone thank her for most of gaster and sans' moments asas this wouldn't have been so amazing without her)