Okay, so here's part 4! I do want to say something before we begin. I do want you guys to give criticism for my story. I will not answer to negative criticism, but will for positive. I want to know how you guys feel about the story, and how you guys would like me to improve it in spots that need it. But other than that, we're all good! I hope you guys like Part 4!

Disclaimer: I do not own Undertale or anything that is in it. All rights go to the creator, Toby. Enjoy!
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[First Person]

As Frisk, Sans, and I go outside, I look around, amazed by how white everything is.

"Hehe are you surprised?" Frisk giggles. "It is winter time right now, so that would explain the snow. That's what all this white stuff is."

As they explain more, I look around and see others, both kids and monsters alike, playing and having fun. I smile softly as it fills me with an unexplainable warm feeling.

"Are you alright, kiddo?" Sans asks.

"Ah!" I jump back and into Frisk, making us both fall into the snow.

"Woah. You kids alright?" Sans walks over to us, clearly worried.

I groan and sit up, then gasp as I look over to Frisk. "Frisk! Are you alright?!"

Frisk stands up and shakes whatever snow got on them. "Yeah, I'm fine. Did Sans surprise you?" They hold out a hand for me.

"Y-yeah, a bit," I say as I take their hand and stand up myself, shaking off snow as I do so.

"Sorry about that. I tend to scare people unexpectedly," Sans says, winking.

"I see that," I chuckle.

"What we're you spacing out about?" Frisk asks, looking at me curiously.

"O-oh, I was just looking at everyone playing about in the snow. It filled me with joy and happiness," I explain to them.

"Hehe, yeah. It's been a few years already, and some humans are more accepting towards monsters than others," Sans tells me. "We still have a long way to go in a lot of places, but we've come far in other ways. Especially with the help of Frisk here." He ruffles Frisk's hair, smiling.

Frisk giggles and grabs onto Sans' arm. "Hey, we should play a game!"

"Okay, kiddo. What game do you want to play?" Sans looks at them with one eye open.

Frisk thinks for a moment, then gasps excitedly. "How about hide and seek?"

"Sure. Does that sound good with you?" They both look at me.

I nod happily. "I'd love to play hide and seek!"

"Alright, then you count, Sans, and we'll hide. Count to 50 so it'll give us some time. And no peeking this time!" Frisk orders Sans.

Sans puts his hands up. "Alright, Frisk. I won't peek." He then covers his eyes with his arm and starts counting. "One... two... three... four...."

Frisk gasps and grabs my hand, running off towards a clearing of trees with me in tow. Frisk and I soon get there as we giggle and catch our breath.

"We... we should be able to hide here pretty well," Frisk gasps.

I nod, gulping for breath. I look around, taking in the area. "Are you sure Sans'll be able to know where we are? I know that we're playing hide and seek, but I don't want him to get worried about us if he can't find us..." I look at Frisk, a little worried.

"Oh, don't worry. Sans will be able to find us. And if he doesn't, then we'll come out so he doesn't send a search party for us," Frisk tells me.

I shrug and walk towards some trees. "Okay. We should at least hide a little better if Sans does come this way and finds us."

"Great idea!" They run-skip ahead of me, clearly enjoying themselves.

I smile and follow slowly. After taking a few steps, however, my chest starts hurting and I grab it, breathing heavily again.

"Hm?" Frisk turns around, noticing that I wasn't catching up. They see me kneeling down in the snow and gasp, coming up to me. "Are you alright?!"

Clutching my chest, I look up at Frisk, my vision blurry from the pain I was feeling. "F-Frisk..." I call out weakly before blacking out.

Frisk grabs me and shakes me, trying to get me to wake up. "Hey, wake up! Someone, please, help-!" As they call out for someone to come help, they're cut off as they look down at me. Their eyes widen as they see my form start to shift.

[Third person]

"45... 46... 47... 48... 49... and 50," Sans finishes counting and uncovers his eyes, looking around. "Hmm.... I wonder where the two runts went to hide." He wonders to himself, then shrugs. "I guess I'll just look around until I find 'em. It can't be that hard to find a monster kid and a human child." He starts off looking for them in obvious places, then goes to more harder places. He sighs and looks around. "Where can you little kids be hidin', huh?" The forest comes into view of his sight, and Sans perks up a little. "Huh. Smart idea, Frisk." Sans walks into the forest, humming/whistling a little tune to himself. He looks around and starts calling out our names. "Hey, Frisk! Kid! You guys in here?" After a few minutes of walking around in silence, he hears someone crying out. "Huh? What was that?" He goes towards the noise and it gets louder.

"S-someone, please help!"

Sans gasps and runs to where the cry for help. When he gets to the clearing, he sees Frisk backing up away from me.

[First person]

As Sans runs up between Frisk and I, his blue eye sparks up. "Wh-what the heck, kid?" What's gotten into ya?"

I look up at him, hissing and growling as my form shifts even more. "Never foooorgettt..." I say to them in a pained voice, reaching for them. My arm falls short from grabbing Sans' foot.

Sans and Frisk both back away from me, both clearly distraught at the fact of my changing form.

"Hey, kid. I'm going to teleport you home, then teleport your... "brother" and I home afterwards. I want you to warn everyone and get Alphys to come to her lab right away. Capiche?" Sans looks down at Frisk.

Frisk nods quickly. "I-I will, Sans!"

Sans waves his hand over Frisk and they disappear with a flash of blue light. Sans looks over at me, sighing in some part relief that Frisk is out of harm's way. "Now, then. Let's get you back to the lab and see what's making you go bonkers. Eh, kid?" With another wave of his hand, both him and I disappear, the forest becoming even quieter than before.

[Third person]

As Frisk teleports into the living room, they look around quickly, and run as fast as they can to the kitchen. When they get there, Papyrus, Toriel, and Asgore are all together.

"Nyeh?" Papyrus looks to Frisk as they enter. "Ah, human! I was wondering when you would come home! Dinner is just about ready!" Papyrus notices that Frisk is out of breath and has a distressed look on their face. "What is wrong, human? And where is Sans and your new brother?"

"Th-they're up in Alphys's lab! I need to get Alphys because something really weird happened to him while we were playing hide and seek!"

Toriel gasps and goes up the stairs, everyone else running after her. "Alphys! We need your help now!"

Alphys comes out of her room, a look of question and concern on her face. "Wh-what is it? What's g-going on?"

"It's my brother! He's in the lab with Sans, and he needs your help!" Frisk quickly explains to her.

"What?! Your bro is hurt? I'll fist pound whoever hurt that little fuzz ball!" Undyne growls.

"O-oh dear!" Alphys and Undyne join the group as they all go to the lab.

[First person]

As Sans and I teleport into the lab, Sans puts a cage of bones over me.

"There we are. That should hold you until the others come," Sans tells me. As soon as he says that, the door to the lab slams open. "Speaking of which, here they are. Took you guys long enough. Nice going, kid. I knew I could count on you," Sans sighs in relief.

Toriel gasps and runs over to my bone cage. "What happened to you?!"

"Woah, Tori. Calm down," Sans tells her softly.

"Don't. Tell. Me. To calm down!" Tori cries out. "Now tell me how this happened to him this instant!"

Sans gulps and sighs. "Look, I dunno what exactly happened to him. One minute, we were playing hide and seek. The next minute, I come to find that he looked like this and was going after Frisk."

They all look at Frisk with worried expressions.

"Wh-what happened to your brother, Frisk?" Toriel asks them with a softer tone.

"Well..." Frisk starts off, "while Sans was counting, we decided to go to the forest nearby to hide. We didn't go far in when I looked back and saw him clutching his chest in pain. When I went up to him, I saw some kind of ooze coming out of him. Like the ooze that Chara has whenever they do that really scary face, but yellow. When I got close enough to see why he was in pain, he grabbed my shirt and said 'Never forget', or something along those lines. Afterwards, I called for help, and that's when Sans came along."

As Frisk finishes explaining, everyone looks at me. I have grabbed one of the bones and was trying to know my way out of my little makeshift prison. Toriel comes up to me and kneels down.

"Be careful, Tori!" Asgore says, clearly unsettled as everyone else is.

Toriel looks at me, kindness and sadness in her eyes. "What or who made you like this, my child?" She asks me gently. I hiss and swipe at her, missing by just a few centimeters. She jumps back and Asgore pulls her back gently, putting her behind his bulking body.

"Never forget," I hiss out to them all, more yellow ooze coming out of my mouth and eyes.

"Alphys, see if you can see what's going on," Undyne says.

Alphys nods and goes to the keyboard. She types in something and a few electronic devices comes out and starts scanning me. I hiss at them and rattle my prison. "I-I'm going to scan him to s-see why this is happening a-and what's making him l-like this," Alphys explains. When the scanning is complete, some stuff comes up on the screen of her monitor. "O-oh my..." she whispers.

"WHAT IS IT, ALPHYS? DID YOU FIND SOMETHING WRONG WITH HIM?" Papyrus asks.

"W-well, it seems th-that whatever is doing this to him, is... i-is..." Alphys gulps, clearly shaken up about the information she just gathered.

"Is... what, Alphy?" Undyne softly asks her.

Alphys looks at everyone. "I.... think that wh-whatever's doing this to him is t-trying to get out."

"Trying to get out? What do you mean by that?" Asgore pipes in.

"I-I don't know! All I do know i-is that our f-friend here is unstable," Alphys hurriedly explains.

"Uh, doc? Not to be rude or anything, but what do you mean by 'unstable'?" Sans calls out. Alphys turns to the computer and gets some stuff up onto the screen.

"Y-you see here? This is his soul. I had to mix a small dose of d-determination with it to stabilize it, and it worked! B-but I do know that it's not the determination I put in h-him that's doing this. Whenever monsters have effects like these, they usually m-melt into more of a gooey substance. The yellow 'goo' that's coming out of his eyes a-and mouth is yellow, but h-he still has his solid form. Which leads to the c-conclusion that he is, in fact, capable on handling s-small doses of determination," Alphys tells them all.

"But what is making him act like this?!" Toriel cries out, clearly distraught over the situation. "My child is becoming something else entirely, and I want to know what's doing this to him!"

Everyone jumps at her sudden outburst. Alphys fumbles with her glasses for a few seconds and brings up the scanning results.

"Now when I s-scanned him, I noticed that there was another s-soul other than his own," She tells everyone as she puts a video of the scan on the screen. "I barely noticed it myself u-until just recently."

She plays the video over once, and everyone just stands around, not knowing what to say or do after it's over.

"DO YOU MIND PLAYING IT OVER? I DIDN'T SEE ANYTHING OTHER THAN HIS SOUL," Papyrus tells her.

"O-oh, of course!" Alphys plays it again, but this time pauses near the end. "Th-this is where the soul pops up." She goes back a few seconds, keeping the video paused. She then clicks on a spot on the video and it gets closer. "S-see the white dot there in the corner?"

Everyone comes closer to the screen as everyone squints to see it.

"I DON'T SEE ANYTHING," Papyrus says.

"Probably because you're too close to the screen, Paps," Sans tells him, chuckling. Papyrus grumbles.

"I see it!" Frisk calls out, pointing to the screen. Everyone gathers around and looks at where they're pointing at.

"Huh, would ya look at that? It is a small world after all."

"SANS! THIS IS NO TIME FOR PUNS!"

Alphys gets the computer to get closer to where Frisk had pointed. When it comes more into view, a tiny soul is indeed showing.

"Wh-what does this mean? Alphys?" Toriel turns around to face her.

"W-well, I'm afraid it means that there's only one reason," she says. "And that reason being is that the person- or plant, in this case- that he was before is trying to get out again," Alphys tells them.

All of the sudden, I cry out in agony and pain, making everyone jump again. Holding my head, I shout, "Stop! Stop this all! I just want to live!"

"What the hell is going on with him?!" A voice cries out from the entrance. They turn around to see Chara standing there, a look of fear on their face. They race over to the makeshift prison, kneeling in front of it. "Get him out, now!" He orders Sans and Papyrus.

"Look, kid; I wish I could, but it's not safe to-" Sans starts up.

"NOW!" they yell.

Sans sighs and slowly takes the prison away.

Chara grabs a hold of me, embracing me into a full on hug. "Calm down, I'm here!" They try soothing me, but I keep crying out in pain and struggle against the hug.

Toriel starts to come towards us when she's stopped by Undyne. She motions to Sans, and Toriel realizes that Sans' eye is glowing brightly. She nods and looks worriedly to us.

"I said STOP, Asriel!" Chara cries out, angry about me not stopping.

As soon as Chara shouts out that name, I stop struggling. I become stationary, almost statue-like.

Chara notices this, but doesn't pull away. "Look, I know you want to live. I know how that feels, truly. But you can't fight like this. It will literally tear you- and others- apart. But it will happen to you most of all." At this point, Chara had come down to a whisper only I could barely hear. "All I ask is that you give this a little more of a chance. I know it's going to take some time getting used to, but you have to realize that Asriel won't remember you right away, you little goat-plant. Give it more time, and I'm sure he will remember you over time."

After about a minute or so, my body begins to relax until it's finally slumped up against Chara. They sigh in relief and pull back, but doesn't pull away from me.

"I th-think it's safe to-" before Alphys could finish, Toriel is already running up to Chara and I.

"Are you alright, Chara!? What were you thinking? You could've gotten seriously injured!" Toriel rants off to them.

"Mom, I'm sorry. I didn't even know what was going on until I started hearing a big commotion going on in here. When I came in, all I could see was Asriel in the cage, screaming and crying in pain. I... I had to do something," Chara explains, clearly worried about me.

Toriel sighs and becomes a little calmer. "I know you are worried about him, as we all are. But you need to think about things, like your safety," Toriel tells him in her motherly soft tone.

They nod solemnly, looking at my now limp body. "I know, Mama. And I will in the future..."

Everyone comes up to us.

"IS... IS HE GOING TO BE OKAY?" Papyrus asks.

"Yeah, he's gonna be alright, Paps," Sans tells him. "He just needs to get cleaned up and some rest will do him just fine." Papyrus nods happily.

Toriel picks me up carefully, not wanting to further hurt me in any other way, or wake me up. "I'll get the yellow goo off of him. Afterwards, I'm going to be with him for awhile."

Before Toriel leaves, Alphys comes up to her with a small jar in her hands.

"N-not to be rude, Tori. But I want to run some tests on the yellow goo. J-just so I can see why he reacted the way h-he did, of course."

Toriel slowly nods. "Alright, scrape some off, and start analyzing it as soon as you can. I'm still worried that he'll..." she doesn't finish her sentence, but Alphys understands and nods. She scrapes some of the goo into the container and hurries off, sealing it as she does so.

"Hey, Paps. Why don't you take Chara and Frisk out for some nicecream? I'll be staying here with Alphys and Toriel," Sans tells Papyrus.

"NYEH! THAT'S A GREAT IDEA, SANS! WE'LL GO RIGHT AWAY. FRISK, CHARA, COME! I SHALL TAKE YOU OUT FOR SOME NICECREAM!" Papyrus marches off.

"Make sure you don't hurt my brother," Chara growls at him, following Papyrus.

Frisk looks at Sans. "Please make sure he's alright and we'll. And... make sure that my mom is alright too, please." They run off to catch up the Chara and Papyrus, leaving Sans to himself (mostly).

"Don't worry, kid. I won't let anything happen to anyone," Sans says more to himself as he watches the three of them exit out of the room.

[In my room]

As Toriel is drying me off from the bath, a knock is heard on the door. She looks up to see Sans standing there, and she smiles softly.

"Hello, Sans. How is everyone doing?"

"Well, Papyrus took Chara and Frisk out for some nicecream, Asgore and Undyne are at the 'gym' practicing, and Alphys is currently researching the yellow goo," Sans tells her. He comes up to us. "How's the kid?"

"Still out cold. Whatever Chara did and said to him, it seems to have calmed him down quite a bit."

"Hehe. I guess Chara knocked him out cold." Sans chuckles, making Toriel smile and chuckle as well. She starts to pick me up, but Sans interrupts her. "I'll pick him up, Tori."

"Are you sure you can handle it?"

"Sure I can, Tori. It'll be no sweat. I have a lot of backbone to back me up." He picks me up, grunting a little. When we get to my bed, he sets me down and let's out a woosh of air. "Kid was a bit heavier than I thought he would be."

"Thank you, Sans. You were very helpful." Toriel smiles and sits down next to me. Sans does the same, looking between me and Toriel. "Do you think he'll be alright, Sans?"

"Of course he will, Tori. He just needs some rest is all. Plus, with Alphys seeing into why he's acting up like this and looking into the yellow goo, we'll have an answer in no time. Plus, he has an amazing mother looking after him." Sans smiles and looks at Toriel.

Toriel blushes and smiles even more. "Thank you, Sans. I'm glad you were able to be here and help."

"No sweat. It's what I do, Tori." Sans gets up. "I'm going to go get a glass of water. You want anything while I'm down there?"

"No thank you, Sans. I'll be fine," she says. He nods and goes out the door, leaving Toriel and I alone.

Toriel looks at me, a solemn look upon her features. "I do hope you will be alright," she says out loud, more to herself than to me.
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Sorry for the long wait, guys! With everything that's been going on, it's been a little hard trying to update and finish part 4. But here it is! Like I said before the story started, I do want feedback on how I'm doing on my story. But I do hope you like it! I'll start on Part 5 as soon as I can. Toodles!