POW POW POW
Frisk was dodging left and right, trying their best to dodge the virtually never ending stream of magic attacks. But who was it that would dare fight such an innocent youth who would never harm any monster.
?: Fuhuhuhuhu…!
Oh, dear. There is only one monster who laughs like that. Undyne!
Undyne: You're gonna hafta try harder than that if you wanna beat me kid!
Undyne started unleashing a volley of spear attacks against Frisk, who just kept dodging. Unfortunately, they stepped on an area that was covered in glowing cyan circles and they knew what this meant. Luckily, they managed to jump back, out of the way before the spears emerged from the floor. Frisk was getting tired and didn't know how much longer they would last.
Undyne: C'mon, kid! Attack me!
Undyne jump straight towards Frisk, a magic spear in both hands. Just when she was about to land right in striking distance, Frisk shot one of their arms forward and grabbed Undyne by the soul which was now blue. She stared at Frisk for a moment, caught in the human's blue attack.
Undyne: … Are. You. KIDDING ME?! AGAIN WITH THIS WEAK SAUCE?!
Frisk hung their head shame, and lowered Undyne.
Undyne: Grrrr… Frisk, I like you and all, but FOR THE WHAT-EVER-ETH DARN TIME, NO SKELETON MAGIC! Seriously, Frisk, I'm supposed to be teaching you how to use and control your spears, but I can't do that if you just keep dodging and not actually fight back!
Frisk: *You ask Undyne why you're even training this way at all and tell her that your parents, Sans and Toriel, have been teaching you to use your skeleton and fire magic by having you throw your attacks at regular targets.
Undyne: Yeah, that's great and all, but I'm trying to teach you how to defend yourself in a fight.
Frisk: *You remind Undyne that humans and monsters have been at peace for almost a year now. Monsters have no reason to fight anymore.
Undyne: Yeah, well you still have to at least try and defend yourself. You never know when someone or something might come at you and attack! And I didn't see you throw a spear once!
Frisk: *You tell Undyne that you don't want to hurt her, or any of your friends.
Undyne: Ha, seriously?! Have you forgotten who your talking too?! They don't call me "Un-Dyne" for nothing!"
Frisk: *You ask Undyne, "Because it's your actual name?"
Undyne: Uh, never mind that. Bottom line is, I'm a boss monster! Meaning it'll take a lot more than a few of my own attacks to beat me! So relax about it. In fact, go right ahead. Hit me with your best shot! I won't even move a muscle.
True to her word, Undyne stood there with her arms out, waiting for Frisk's attack, fully confident that it wouldn't even hurt that much since they only had 1 L.V. Frisk was hesitant, but summoned a spear nonetheless. They took aim, but the young pacifist couldn't bring themself to do it.
They were about to tell Undyne that they couldn't do it, but then stopped. Something about this seemed far too familiar. Just Frisk and Undyne, alone in a fight, and Frisk ready to attack. It made them feel uneasy.
Then everything flashed. It was only for about half of a millisecond, but Frisk saw enough. During this flash, the scenery changed to the long bridge past the waterfall in the Underground. Undyne was right in front of them, injured. She had a large gash going right down her chest, and she was turning into dust. She looked straight at Frisk, glaring at them. And then it was over. Frisk slowly lowered their spear and it soon disappeared.
Undyne: Ah, WHAT?! FRISK, I TOLD YOU I—!
Undyne couldn't finish, for Frisk had suddenly started crying. They then dropped to their knees and covered their eyes.
Undyne: Uh, hey, Frisk, it's okay! Really, we don't have to train like this if you don't want to! Frisk?!
But Undyne's words could not be heard past Frisk's sobs.
Frisk: *Though still crying, you tell Undyne that you just want to go home.
Undyne: Uh, yeah, sure. I'll take you home myself. C'mon.
Undyne was about to carry them home herself. Frisk usually loved being carried by their friends, but this time they backed away before Undyne could pick them up. It had happened again. The moment Undyne reached out for them, Frisk saw the image flash again, changing Undyne's appearance. She was wearing black-clad armor, had a smile like she was going to enjoy killing Frisk, and her eyepatch was removed to reveal spear shaped lightning emerging from her left eye. And then it was over, but it was enough to make Frisk back away from her friend quickly and immediately.
Frisk: *You tell Undyne that you would rather walk home by yourself this time.
Then, without another word, Frisk got to their feet and left, leaving Undyne confused, but ultimately worried for the young human. After exiting the house, Frisk proceeded down the lawn to the sidewalk on the other side. After looking both ways like the good little child that they were, and seeing no cars coming, they began crossing the street.
While they were walking, but still crying, their mind was focused on one thing, the memories. This version of Frisk, along with quite a few monsters and only a handful of humans, knew The Truth. That they were all fictional characters from a computer game. That also meant that they knew about the Genocide Route. But Frisk didn't just know of it; they lived it… and finished it.
They didn't like the weird feeling of killing a few monster during the Neutral Route, but they did it, just to see what would happen. They had figured out every secret of the game, including the secret room that opens when you dodge all of the credits at the end of the True Pacifist Route, the grey door and the grey people speaking of W.D. Gaster, and then meeting him behind the grey door, and even the meeting with "I'm Sorry". They had even met Red (not game canon). They had done it all, except for the Genocide Route, but then came the fateful day when they tried it.
At first, all of the killing was just because they were curious. It felt wrong at first, but as their L.V. continued to go up, they started to like it more and more. Up until the moment when they met Chara, the first fallen child, and best friend of Asriel. They gave Frisk a proposal, but they refused… Chara didn't accept that. From that moment on, for many gameplays, Frisk was kept a prisoner inside of their own body, forced to watch their friends either befriend someone who wasn't them, or watch them die over and over and over again. They realized that it wasn't their desire to kill that they felt during their first Genocide Route, it was Chara's. They were just using them to get what they wanted, and they succeeded.
The false befriending or the constant killing, it would have gone on forever, until Frisk did something that only Flowey had ever done; they crashed the game. However, in order for them to achieve this, they had to do the exact same thing that Chara did; they waited until Chara had collected enough monster souls on the Genocide Route and used their own determination to steal their power for them to use. It wasn't an easy feat, however, since Chara's determination was very strong.
Frisk had to find the right moment, and that moment presented itself when they faced Sans once again. Because he attacked so quickly and so often, Chara had to focus all of their attention on his attacks. That meant, they weren't focusing on using their determination to keep Frisk away from the souls that they had absorbed.
Of course, when Frisk tried to use the power of the monster souls, Chara found out immediately, but they reacted too late to stop them, for they had been hit by a particularly powerful attack by Sans, and the pain was excruciating, which made for a good enough distraction. Because it was originally Frisk's body, they felt it too, but they fought through it, and used the power of the souls and their own determination to crash the game, only this time, the game software as a whole was forced to reset completely. It was as if it were just downloaded. By the time the game started up again from the beginning, Frisk was once again in control, and Chara seemed to have disappeared.
From there, Frisk was able to play through the True Pacifist Route one final time. "Final" meaning that once they freed all of the monsters, they made a solemn vow to never reset the timeline ever again. However, for the past few days, not long after they were given their "accidental gift", they started having terrible nightmares composed of those horrid memories.
Normally, they would just ignore it, but that training session with Undyne… what she told them to do… and what they saw when she said it… Frisk's friends already knew the truth about their existence, but they never remembered the other timelines. They only figured that Frisk had just done nothing but the True Pacifist Route seeing as how they didn't reset.
As Frisk entered their home, they were greeted with the sound of their mother's voice from the kitchen.
Toriel: Frisk? Is that you? Your home early. I just got finished baking you a butterscotch-cinnamon pie. It's still hot, but—
Frisk: *Though still sobbing, you tell Toriel that you're not hungry. She seems to notice the sobbing.
Toriel poked her head out of the kitchen in response to the sound of crying.
Toriel: My child? Is something wrong? Why are you crying?
Frisk: *You tell Toriel that you just want to go to bed right now.
Toriel: Right now? My child, if there is something troubling you, you can tell me.
Frisk didn't answer. They merely walked up to their room without another word. They locked the door, and sat down on their bed, pulling their knees up close to their face. For hours, they stayed in there. They didn't like thinking about the Genocide Route, and managed to avoid things that brought it up, until now.
KNOCK KNOCK
Frisk: *You instinctively ask "Who's there?"
?: Old pen, says…
Frisk: *You can tell where this is going. You feel a little better, smile, and then reply saying "'Old pen, says', who?"
?: Old pen, says-a-me!
Frisk: *You stop crying and start laughing instead, as a result of hearing one of your Dunkle Sans' bad jokes. You hear your dunkle laughing with you and feel better enough to open the door. You greet Sans with a smile and thank him.
Sans: Eh, no problem. It's what I'm here for, kid.
Sans sat down on Frisk's bed with the child sitting beside him.
Sans: So, any reason why you turned down one of your mother's famous pies?
Frisk turned their head away from Sans. They didn't want to think about it, but Sans pressed forward.
Sans: C'mo-on, you can talk to me. Is it your grounding? 'Cause you've been particularly good recently. I might just be willing to talk to your mom about reducing it.
Frisk: *You tell Sans that that's not it.
Sans stared at them curiously at first, and then decided to continue his questioning.
Sans: Uh… Alrighty then, maybe Undyne went too hard on you during training? If that's the case—
Frisk: *You tell Sans the reason your alone is because Undyne told you to… attack them.
Sans: Oh, wow… heh, oh jeez. Don't tell me it's…
Frisk nodded in response. Since Sans was one of the few monsters who knew that they were all just video game characters, that also meant that he knew about the Genocide Route. He even once questioned Frisk about the Genocide Route, and they told him everything, despite them being somewhat afraid of how he would react to hearing how the child he became friends with also ended up beheading his only brother by punching it off with a hit glove. He actually took it pretty well and forgave them afterwards.
Sans: (sigh) I guess it can't be helped, what with those nightmares you've been havin'.
Sans, Toriel, and Papyrus all knew about their nightmares. They did their best to help the child get rid of them, but recently, have come up short. The nightmares had gotten so bad, that Sans had even caught Frisk sleepwalking on a number of occasions. The only thing that had the best results was the time when they all camped out in the living room, despite Frisk being grounded. Unfortunately, that resulted in Toriel having sever back pains caused by sleeping on the floor. So, for the time being, Frisk was bunking with Papyrus, but the nightmares still came back.
Sans: Tell you what, you come downstairs and get something to eat, and we can all talk about this.
Frisk agreed to the terms and followed Sans downstairs.
At dinner, everyone was enjoying a special serving of Papyrus' famous gourmet spaghetti. All of those cooking lessons he took paid off, because he now worked as a pasta chef at a local restaurant, specializing in monster-style spaghetti. Of course, that was because he started taking cooking lessons from Toriel rather than Undyne, as per the usual routine.
Once everyone was done eating, Sans brought up the topic at hand; Frisk's nightmares.
Papyrus: No worries, human! Your cool friend, the Great Papyrus, has recently purchased a far stronger nightlight! Surely that should be enough to keep the night-terrors at bay!
Sans: Actually, how about tonight, we have another camp out in the living room?
Papyrus: Another marvelous idea! No wait, won't miss Toriel get hurt that way?
Toriel: It's fine Papyrus. I'm sure I'll manage for one night, but why Sans?
Sans: I just think that our kid deserves a good night sleep tonight.
Toriel sensed that her husband had other motives, but couldn't figure out what they were. After a nice, albeit slightly cold, butterscotch-cinnamon pie for dessert, they all gathered in the living room for a nice camp out, the only thing that seems to work in helping Frisk with their nightmare problem. Toriel sang Frisk a lullaby to help them sleep and they soon drifted off to dreamland, unexpectedly followed by Papyrus.
The lullaby that Toriel sang to Frisk was the melody from the music box inside of the statue. It plays after you give the statue an umbrella.
About an hour later, everyone had fallen asleep. Everyone except for Sans, that is, ironically. He was about to put his plan into action. He had experience with dealing with nightmares of the Genocide Route. More than he could remember, given all of the resets. In the beginning, Papyrus started having terrible dreams of all of his friends dying, and he not being there to stop it. In fact, in his dreams, he was nowhere in sight. It all ended with Sans being killed.
When Sans saw how much distress this was causing him, he did something drastic. He used his magic to connect to Papyrus' subconscious mind so that he could rid him of his bad dreams. It worked, but then he started having them instead. He later found out why Papyrus wasn't there to stop his friends from dying; because he was already dead. Sans could pass it off as nothing whenever his brother would ask, but it still bothered him. The nightmares only stopped after Frisk freed the monsters from the Underground.
Now his adopted child was being tormented by them. He knew that what he was about to do would most likely result in the dreams being passed on to him, but he didn't care. He was used to it, so he could handle it… right?
Sans (in thought): Welp, either way, no goin' back now.
Sans got up and looked over at Frisk. Just as he thought, they were sleeping peacefully, just like last time. Sans smiled, watching his child snuggle up against his wife so happily. They and the rest of his friends were as much family to him as Papyrus was. Even more so, now that he was legally their father. He felt that he had to do this.
Sans: (sigh) Here we go.
Sans reached his hand out and suddenly, his left eye started glowing blue. Seeing as how they had his M.M.E. inside of them, it shouldn't be too hard to connect with Frisk. He closed his eyes, focused his magic, and felt the connection.
Opening his eyes, he could see the confines of Frisk's subconscious mind unfolding before him as if he were physically inside of their head. Sans searched around for a while and found nothing, which was odd. When he was inside of Papyrus' mind, the nightmares took the form of a dark cloud swimming around in Papyrus' head. Here, Sans couldn't find anything that looked remotely like that.
Sans: Where are you, you big wad of trash?
Suddenly after he said that, he heard something.
?: (giggles) You shouldn't be looking for a "what". You should be looking for a "who".
Sans heard a voice. A child's voice that resembled Frisk's but was slightly higher and sounded somewhat creepy.
Sans: What the…? This isn't right.
?: No, it isn't. You shouldn't be here, Sans.
Sans: You can talk to me?! Where are you, ya little nightmare?
The child's giggle soon grew into a laugh.
?: You think I'm just some bad dream? You think I'm just some trouble you can "throw away in an old gym bag and smile"? (laughs) Oh, no. I'm something much… much worse.
Sans: Then who are you?
?: Frisk thought that they got rid of me when they crashed the game, but they were wrong. They just buried me away in the very back of their mind. With no power, I couldn't do anything. I could only watch them enjoy their pathetic, happy life. Disgusting. But then, they had their little… hm… accident in Alphys' lab and got magic. Monster magic. That gave me enough power to have a bit of fun with them.
As they spoke, Sans began to put the pieces together. He then knew who he was talking to. The very character who only made a physical appearance at the end of the Genocide Route, Chara. Almost as if they knew he had figured it out, Chara appeared before him like a demon made of blood.
The heart that represents Chara's soul in this story looks like it's contaminated with some kind of deadly virus that spreads from the center out.
Chara: Long time no see, Sans.
Sans: I can't even remember the Genocide Route, and it's still not long enough. So you're the reason Frisk has been having nightmares?
Chara: Yes, that would be my handy work. And it's all thanks to Alphys' little experiment.
Sans: Well, I'm only gonna tell you this once, get out of my kid or—
Chara: "I'm gonna have a bad time"? "I'll be dead where I stand"? Now let me see, how many times have you told that to Frisk or me? Gee, we both played through the Pacifist, Neutral, and Genocide Routes so many times I've actually lost count.
Sans: Well, I'm not gonna let you stick around here any longer. Even if I have to drag back to my own mind, you're out of here.
Chara: (giggles) Seriously? You seriously thought I was planning on staying here for the rest of my after-life? You seriously thought I was content with giving Frisk nightmares forever? (laughing) No, I've just been waiting for my power to become strong enough so that I can get out of here myself. Then, with the power I've been draining from Frisk, I'll be able to do what Asriel didn't have the guts to do. I'll destroy all of man-and-monster-kind!
As Sans heard their evil plan, he grew more and more determined not to let it happen.
Sans: Yeah, no way I'm letting that happen.
Chara: (giggle) You idiot. My escape is already in progress.
Sans: What?!
Chara: Remember the sleepwalking? That was me trying to get Frisk to do what I needed them to do so that I can leave. But every time, you stopped them before they could do it, but not this time. You see, during the first time you all camped out downstairs, I just didn't bother to give Frisk nightmares so that something like this wouldn't happen. But then I came up with the genius idea of using such a situation to my advantage. So, I just kept giving Frisk nightmares and kept feeding off of their magical energy, hoping you would eventually take care of the rest. And now here we are. In Frisk's mind, and while we're here talking, Frisk is about cut their hand with a kitchen knife in three… two…
Sans: NOOOO…!
Sans snapped out of his trance in time see Frisk, in the kitchen, already running the blade down the palm of their left hand.
Sans: FRISK, WAKE UP!
Toriel: AHH! Ow!
Papyrus: NYEH?!
Frisk: *?! You wake up to the sound of Sans' voice, but you feel a sharp, searing pain coming from your hand. Looking down, seeing the cut in your left hand and the knife in your right, your only response is to scream.
Frisk dropped the knife and held their hand to try and limit the amount of blood coming out of it. They dropped to their knees screaming, crying out in pain. In an instant the monsters that were their family hurried to their side. Toriel tended to Frisk, and Papyrus was sent upstairs to fetch the first-aid kit. Sans, on the other hand, was looking for something out of the ordinary, and found it.
Sans: GET BACK HERE, YOU DISGUSTING SLIME!
Toriel held Frisk tightly after witnessing Sans scream and throw bone attacks at nothing, but Frisk soon saw what he was attacking and immediately alerted their mother. Then Toriel saw it, a small pool of blood, Frisk's blood she had to guess, moving on its own, trying to avoid the bones being thrown at it.
Papyrus: Sans?! What are you doing, brother?!
Sans: Papyrus, help me!
Papyrus: Eh?!
Toriel: Papyrus! The blood! It's moving on the floor!
Toriel pointed to the living room, in front of Papyrus, and he saw just what she meant.
Papyrus: Whatever you are, you are frightening my family, and that is something the Great Papyrus cannot allow!
Papyrus then started throwing his own bone attacks at the moving pool of blood. Sans was overcome with rage. He didn't want to stop the blood. He wanted to kill it. Or more specifically; them.
Sans: YOU SICK! DISGUSTING! SADISTIC! COLD-HEARTED! DIRTY BROTHER KILLERRRRRRRRRRR!
At that moment, Frisk finally understood what it was. They had only heard Sans refer to one person by that name; themself during the Genocide Route. It was Chara. Frisk only had one way to respond to that at the moment; by doing something they didn't like to do; attack. They summoned a magic spear in their right hand and threw it right at the pool of blood, but it just avoided it.
The pool of blood just kept avoiding attacks, but then moved in front of the stairs. Sans was readying a bone attack when it sped straight for where Papyrus was standing on the stairs. Sans didn't notice until he finally threw his attack that Papyrus was in the line of fire, he used his blue attack to throw Papyrus out of the way. At that moment, while Sans was distracted and Papyrus was being thrown, the pool of blood made its way for the door.
In a final effort to stop Chara, Frisk ran their right hand over their right eye, thus activating their full power spear magic and making it look like they had spear shaped lightning coming from their eye. They shot their hand out, causing several large cyan circles to appear on the floor, in front of the door. Just as they were about to skewer the living blood puddle, Undyne herself came bursting through the door, spears at the ready.
CRASH
Undyne: YEAH! I HEARD THE SOUNDS OF A FIGHT! WHO'S THE PUNK WHO NEEDS TO BE TAUGHT A LESSON?!
Frisk instantly stopped their attack as soon as they saw Undyne standing right on top of it, allowing Chara to slip right underneath her.
Sans: UNDYNE, STOP THEM! DON'T LET THEM ESCAPE!
Sans pointed right behind her, and she instantly responded by throwing her spear behind her. She missed by a mile, and knew it as soon as she saw that what she was supposed to be aiming for was a puddle of living blood. She tried to rectify this by chasing it down and throwing more spears at it, but it was no use. Chara had reached a nearby sewer drain and flowed down it. They had gotten away.
Undyne turned back to the blended human/monster family. Papyrus was picking himself up off of the floor, Frisk's eye had turned back to normal, but they were still in pain, Toriel was holding them while grasping their left hand tightly, and Sans was staring at the floor.
Toriel: Papyrus, the first-aid kit!
Papyrus suddenly remembered what he was sent upstairs to get. He quickly grabbed the kit off of the ground and hurried over to give it to Toriel. She immediately began using it to help tend to Frisk's injured hand.
Undyne: Okay, someone wanna tell me what—the heck—that thing was?
Sans raised his head to look her, dead in the eye.
Sans: A big problem.