How about a medium problem as well?
"PUT THE FUCKING CHEMICAL DOWN YOU CRAZY MAN!!" Frisk said as she turned around and saw Gaster was doing something behind her back.
"I JUST NEED THAT CHEMICAL THAT MAKES THE CELLS GO BACK IN AGE!!" Gaster yelled. Frisk frowned.
"Listen...every time you do that.....I TURN INTO SOMETHING THAT I SHOULDN'T TURN IN!! SO STO--" This time, the man poured the chemical on her out of spite.
"Oh i hate you so much..." She said, before she started shrinking. She was now a toddler. Alphys walked in.
"Gaster I-....T-This t-time i-i didn't even walk in....you know what..? screw this..." Alphys said turning around and leaving. Gaster stared in disbelief at the little toddler.
"Oh. My. God...I was so close..." He said with a sigh. Little Frisk however still hadn't reacted. Gaster knelt down next to her.
"Hello there little one." He said with a smile. Frisk looked at him dully and tilted her head.
"....hi..." She said shily. Gaster's gaze softened.
"Are you ok, child?" Frisk shrugged.
"....dunno....umm...where am i ....?" Frisk asked looking around. She was probably 6 or 7 years old. Gaster tried to reach towards her with his hand. She flinched and backed away a step or two. Gaster looked sad at the little girl.
"Don't worry...i won't hurt you...I am just here to help ok...? Let's go back to my house..." Frisk scrunched up her nose.
"...you're probably a pedophile...The raggy clothes...the dumb excuses...the house...yeahhh no, thanks..." Frisk looked around some more.
"Is this where you take the kids...?" She asked. Gaster was stunned. Frisk didn't trust anyone nearly as easily as she did when she fell in the Underground. She was so...closed off...
"No child...listen, i am the royal scientist of the monsters." Frisk raised an eye-brow.
"What are you, chupacabra? Yeah, no thank you, sir." Frisk was about to leave when Gaster sighed.
"I am your guardian now." Frisk froze. She turned around.
"My parents.....gave me away....?" She asked in disbelief. Gaster realized just how bad that may have sounded in her head.
"They...they actually got rid of me.....FUCK!" She said kicking the ground. The little kid inhaled and exhaled.
"Fine...let's just go..." She said as she walked behind him. She refused to walk forward without him in front of her. She was a smart child. That's for sure.
"What is this..? La dias de los muertos..? Why are there so many skeletons..? Am i in the after life or something??" Frisk asked as she looked at the two skeletons who were staring at her. She looked so...dull...
"soo...you're telling me you aged frisk down again...?" Frisk backed away.
"how do you know me??" She asked. Papyrus came forward.
"DON'T WORRY TINY HUMAN!! I, THE GREAT PAPYRUS, WILL PROTECT YOU FROM ANY HARM!" Frisk looked him up an down.
"I'd rather have your dad protect me...someone your size i can take down with my eyes closed....but thanks for the gesture, the thought counts." She said with a small nod. She looked around the house. The two children were taken aback at her attitude. That wasn't the Frisk they knew. She really did come a long way, huh?
"Little one, do you want something to eat...?" Frisk raised an eye-brow.
"I'm allowed to eat...?" She asked confused. The skeletons froze, their sockets going blank.
"in how long....haven't you eaten...?" Sans asked, his voice cracking a bit. Frisk frowned.
"maybe 3 days...maybe...i'm not sure what day it is today...anyways...if i can actually eat, i would love some food." Gaster's gaze softened again. He tried to put a hand on her head, she flinched and hit his hand. The two kids watched stunned. Gaster retracted his hand.
"sorry...no touching please.." Frisk said. Sans sighed.
"this will be a hard day..."
Frisk was...obedient. She didn't question anything, she just did. She would always take orders. However Sans was working on something else. Making her open up. The two were sitting on the floor and were looking at each other. Papyrus was waiting on the couch.
"You feel familiar...it's creepy." Sans snorted.
"really, kiddo?" Frisk nodded.
"I like how it feels...but i don't know why..." Papyrus looked at his brother. Sans smiled. He put a hand in her hair and ruffled it. Instead of flinching away she leaned in and smiled, blushing a bit. Sans smirked.
"i see your soul still knows who i am, kiddo." Frisk tilted her head.
"Are you someone important?" He chuckled.
"i like to think so...heh." Frisk narrowed her eyes at him.
"I think you are...dunno...just a feeling..." He sighed and his gaze softened.
"heh. even as a kid you're sometimes dumbly nice..." Frisk smiled a bit, for the first time since she stepped foot in the skeleton's house as a toddler. Papyrus beamed.
"BROTHER, YOU MANAGED TO MAKE HER WARM UP!!" He said jumping up. Frisk looked at Papyrus and laughed a bit. The two skeleton's stared at each other and smiled.
"Why would you be so happy that i warmed up a bit..? That's so funny!!" Gaster came in the living-room and saw toddler Frisk laughing. He smiled at the sight.
"Come on, it's dinner time." Frisk's eyes lit up.
"i never ate two times in a day..." She said. Sans froze. He knelt down next to her.
"don't you ever dare think that it's normal...eating 3 times a day it's normal...and i promise you, you will have a better life here..." Frisk's eyes swam with tears and she hugged the skeleton. That took all 3 of them by surprise. Sans returned the hug.
"Thank you..." He sighed and patted her head.
"don't worry about it, kiddo..."
Sans walked over to Frisk's room to see how she was doing...plus, out of habit...He was surprised to see that Frisk was still awake. She was sitting next to the bed awkwardly.
"wassup, kiddo?" Frisk was startled but when she saw it was Sans, she calmed down.
"can't sleep, bucko?" Frisk shook her head.
"That...and i guess the fact it's really quiet it's throwing me off..." Frisk said cradling her knees to her chest. Sans sits down next to her.
"you know...usually when you couldn't sleep or i couldn't we would sleep together." Frisk looked at the skeleton.
"W-would y-you...?" Frisk asked. Sans smiled.
"sure buddy. come on." Frisk smiled and jumped on the bed. Sans laid there as well. Frisk hugged his arm since she was smaller than him. He chuckled.
"night bucko..."
The next day went of fairly well. The three skeletons tried to keep a bit of a distance between the kid and them since she now was a total stranger so to speak. That is until their friend marched in their homes, pitch-forks ready, for Gaster since he transformed Frisk again. The kid was now hiding behind Sans.
"Aww...she's so cute." Frisk tilted her head.
"You look like something chupacabra would eat...And you look like human shushi." Alphys snorted as Undyne stared at her in disbelief.
"WHAT DID YOU SAY YOU BRAT??" Frisk backed away as she raised her tone.
"S-SORRY!!" She said bowing down. The kids were left stunned.
"woah kiddo hold up, you don't have to bow...come on." Frisk nodded and sat up properly. Undyne looked away.
"Now i feel bad." Sans gave her a dangerous look.
"i would have been worried if you didn't..." He said. Undyne put her hands up in defense.
"W-well i-i think s-she's c-cute..." Frisk nodded a thanks.
"She is...but she's mean.." Frisk shrugged.
"You gotta build some walls to make it...so far i'm failing." Sans stiffened. The kids all froze with wide eyes.
"I don't like that..." Sans sighed.
"neither do i..."
The kids all were loud, but suddenly Frisk started regaining some of the colors they knew. Sans smile grew as she got up and started telling stories or when she laughed. Relief came over his soul as she actually ate. She did however bow down and apologize a lot. Sans grew used to it. Night-time came by quickly. Of course, our lovely skeleton decided he will go to check on Frisk. She seemed to be sleeping. He was about to leave when a little hand caught him.
"Hmm...? You can't sleep..? Didn't you said we used to sleep together...? Come on..." He smiled and laid down with her. She quickly fell back asleep. He brushed the bangs out of her eyes and sighed.
"i can't express how glad i am....that you are doing better...love ya..." And closed his sockets.
Frisk woke up and groaned. Sans heard her and opened a socket lazily.
"Ughh...i feel like i'm hangover or something...everything hurts...WOAH!!" A loud thud let him know she just fell out of bed. He started laughing.
"you ok baby-bones?" She raised a hand and gave him a thumbs up.
"Did i grow or shrink...?" He laughed.
"you were a toddler...and yeah your soul spoke again." She laughed.
"Even as a toddler i knew you were mine. I got dem moves huh?" Sans blushed.
"oh my god, i regret ever saying that..." Frisk started laughing more.
"SOULLLMATEEESSSSS~~" She said wiggling her hands. Sans face-palmed and threw a pillow at her. She threw two back and soon enough they were wrestling on the bed. Of course, Frisk cheated by giving him a kiss and freezing him but he didn't care. After all, a kiss is a kiss and a kiss from Frisk is 10000 times better.