Under Tail

BY : Fantom
Category: +S through Z > UnderTale
Dragon prints: 30928
Disclaimer: I do not own, or claim to own, Undertale or any related properties. No profit was made in the writing of this story. Please, please support the original game by buying it on Steam.

Long ago, two races ruled over the earth: humans and monsters. One day, war broke out between the two races. After a long battle, the humans were victorious. They sealed the monsters underground with a magic spell.

Many years later…



Mt. Ebott, 201X.

Your hands trembled slightly as you walked your way through the dark woods up the side of the mountain. It didn’t have a very good reputation in your town; legends said that anyone who climbed to the top would never be heard from again. Needless to say, this was the last place you wanted to be.

But you knew that if you turned back now your ‘friends’ would never let you live it down. Their mocking taunts still rang fresh within your mind. “Fraidy cat”. “Chicken”. “Baby”. “You’re such a little kid”.

You knew that they’d stop calling you those names after today, though. Today, you’d be the first person to return from the top of Mt. Ebott in years. As the peak of the mountain came into view, your heart began to swell with determination.

With your goal only a few feet away, you took a confident step forward to reach it. Then, a loud crack suddenly pierced the silent night air, and you looked down just in time to see your left foot be consumed by the earth. You tried to let out a scream, or to grab on to something, anything, but both your mouth and your limbs failed you as you found yourself another victim eaten by Mt. Ebbott.



It wasn’t until you woke up again that you realized that you had blacked out. You immediately checked your body for any injuries but, fortunately, nothing seemed to be broken or even bruised. You looked up to see that the hole you fell through was at least six stories above you, but your fall seemed to be perfectly cushioned by a layer of soft yellow flowers covering the cave floor.

But, after checking over yourself once more, you began to realize in horror that you were missing something. You didn’t notice it was gone at first, as you never bothered to pay attention to it before, but now its absence was all you could think about. You looked for it again, and again, and again, but every time you checked just reconfirmed what you already knew.

You had no heartbeat.

The idea that you were having a heart attack crossed your mind, but you quickly dismissed it. You could still stand and breathe just fine, and you didn’t seem to have any other symptoms of cardiac arrest. The thought that you might be dead also flashed into your head, but you knew that that was even less likely. Your attempts to theorize exactly what was wrong with you were interrupted, however, by a very familiar sound.

Bump-bum. Bump-bum. Bump-bum.             

You fingers immediately flew to your neck to check your pulse again, but you still couldn’t find a heartbeat. Confused, you began looking around the dark cavern until you found the source of the noise, which nearly caused your jaw to hit the floor.

Floating there in front of you was a small, red heart. Not a squishy, realistic heart covered in veins and arteries, but a crimson, shiny, cartoon heart that sat there pulsing in the middle of the air without any visible support. You reached out your hand to make sure that you aren’t hallucinating and begin rubbing your fingers along its smooth surface. Even though the heart was not actually attached to you, you could still feel the sensation of your fingers running over it as you slowly brought it towards your chest. 

“Why hello there!” a feminine voice abruptly blurted out from behind you. You turned around to see what appeared to be a normal yellow flower at first, but closer examination revealed to be anything but.

The flower was roughly your height and had two long green leaves sprouting from the center of its stem. What really stood out about it, though, was its head. It looked human, but had pale white skin and glowing yellow eyes. It’s long yellow petals came together to form what looked like a moppy blonde haircut, and it had a smile that seemed unnaturally cheery.

Suddenly, the idea of you being dead didn’t seem so farfetched.

“Wowzers! That was quite the fall you took, wasn’t it? You sure are lucky to be alive” the strange flower woman pointed out. “I’m Flowey, by the way. Flowey the Flower. What’s your name?”

You told Flowey your name.

“What a great name!” she said excitedly. “Now, are you a boy or a girl?”

You shook your head ‘no’.

“Faaaascinating” responded Flowey. “Well, since you’re new to The Underground, I guess someone will have to teach you how things work around here, and that someone might as well be me”.

After a moment, you tentatively nodded your head in agreement.

“Alrighty then! You see that little red heart in your hands?” asked Flowey. “That’s your soul! Down here, humans have trouble keeping their souls inside their bodies, but that’s okay! It can do all sorts of cool things, like fly around! Why don’t you try it?”

Reluctantly, you let go of your soul and allowed it to begin floating around the dark room. It was difficult at first, but you were indeed able to control which way the heart went by concentrating hard enough.

“Very good!” praised Flowey, her eyes affixed tightly to your soul. “You’re a natural at this! Your soul starts out weak, but can grow stronger if you gain a lot of LV. What’s LV stand for? Why, LOVE, of course! You want some LOVE, don’t you?”

You nodded your head.

“Don’t worry, I’ll share some with you!” Flowey replied, winking.

After she winked, several little white orbs appeared from behind the flower woman’s back and began to spin in the air behind her.

 “Down here, LOVE is shared through… little white… ‘friendliness pellets’” she went onto explain. “Are you ready? Move around! Get as many as you can!”

The friendliness pellets then began making their way through the air towards your soul, so you did as you were told and began floating your soul towards the glowing orbs. You expected the pellets to feel nice when they touched the little red heart, which caused the moment when they hit and sent a tidal wave of pain into your skull even worse when it finally happened. You tried to call for help, but found your entire body paralyzed by Flowey’s traitorous attack.

“Ha! You moron! I can’t believe you fell for that!” Flowey cackled as her eyes blackened and her teeth enlarged into fangs. “Down here, it’s kill or be killed!”

You tried to run away, but your legs refused to move.

“Aww, don’t look so sad” Flowey said mockingly as she began shifting forward through the dirt towards you. “After all, now comes the best part; I get to rape you! I hope you’re prepared for your first time with a monster, because it’s also going to be your last!”

“Actually, I think you’re the one who deserves to be deflowered” another voice said out of nowhere.

Flowey was able to turn her head just in time to see a fireball smack into the side of her head and send her flying into the darkness surrounding the room. You had just enough strength left in your body to look and see where the flames came from.

What emerged from the shadows was another woman, but this one was much larger; she stood a towering eight feet in height, and had an enormous bust that seemed oversized even on a woman her stature. Her skin was covered in a fine layer of white fur, which combined with her long droopy ears and two small horns on her forehead to make her appear as if she were half goat. She was wearing a long purple dress with white sleeves and a strange looking symbol printed over the chest area. A glance downward revealed that she wasn’t wearing any shoes over her animal like feet.

“What a terrible creature, torturing such a poor, innocent youth” she said contemptuously before turning her attention towards you. “Are you hurt, my child?”

You explained to the woman that, while you were indeed in pain, you are actually over twenty years old.

“Oh my goodness!” she gasped. “You’re even younger than I thought! Don’t worry, I’ll heal you as best as I can”.

Her hands then began to glow as she wrapped her hands around your soul, and you could feel a comforting warmth fill your body. Within just a few seconds, you could move again just as easily as before.

“My name is Toriel, and I am the caretaker of these ruins” she explained she released the heart and allowed it to float back towards you. “I come here every day to see in anyone has fallen down here. You’re the first human to come here in a long time. Come, my child, I will guide you through the catacombs”.

While it humiliated you that she was treating you like a kid, you knew it was best not to look a gift goat in the mouth and followed her as she exited through a doorway behind her. Your soul flew alongside you as you walked, pumping quietly as your heartrate finally began to slow.

Toriel led you through the dark hallways of the ruins until you both arrived at a small, dimly lit room with a firmly closed stone door and several pressure plates arranged in a pattern around the floor.

“Welcome to your new home; The Ruins” Toriel said with a smile across her face. “Allow me to demonstrate how to navigate its rooms”.

She then stepped on most, but not all, of the pressure plates on the floor and then pulled a lever on the far wall, which caused the locked door to begin trudging open.

“The Ruins are filled with all kinds of riddles and games like this one that serve to keep out unwanted intruders” she explained. “One must solve these puzzles in order to move from room to room. They’re a little annoying at first, but you’ll get used to them over time”.

She then proceeded into the next room, which was slightly larger and better lit.

“To pass through this room, you will need to trigger several switches” Toriel said in a motherly voice. “Don’t worry, I have already labeled the ones you need to pull”.

There were three large levers attached to the purple brick wall behind her, two of which had large yellow arrows painted on next to them. Being the incredible genius that you are, it didn’t take you long to solve the puzzle.

“Very good!” Toriel congratulated as the door to the next room began to open. “Let’s move on to the next one, shall we?”

The next room was mostly empty, with the exception of a female looking mannequin about your height standing in the center.

“As you’re well aware of by now, not all monsters you meet down here will be as friendly as I am, and many will even try to attack you” Toriel explained. “It’s not your body that’s in any danger, however; it’s your soul. Human souls are very valuable in The Underground, and there are many who would do anything to acquire one. If your soul is hit too many times by a monster’s magical attacks, then you’ll be paralyzed and vulnerable to having your soul stolen, and if that happens… you die”.

You asked if that has anything to do with Flowey trying to rape you earlier.

“Yes, actually…” Toriel replied, blushing hotly. “In order to take control of a human’s soul, a monster will have to have… intercourse with the human’s body in order to gain dominance over the soul and force it under their command”.

You asked if the same thing happens if the sex is consensual.

“Well, no, but you’re far too young to be thinking about those kinds of things” said Toriel. “Do not be afraid, though. I will help protect your soul, and your innocence, for as long as possible. If you ever find yourself in a fight with a monster, strike up a friendly conversation with them to stall for time. I will then arrive to resolve the conflict as quickly as I can”.

She then walked towards the mannequin and motioned towards it with her hand.

“Why don’t you practice by talking to this dummy?” she asked.

You walked up to the woman shaped object and asked about its day. Rudely, the dummy did not respond in any way.

“Well done!” Toriel said, clapping her hands. “Now then, continue to the next room”.

You followed behind Toriel and soon found yourself in room with a large moat bisecting the room and a bridge covered in spikes spanning over it.

“Hmm, I wonder if you can solve this puzzle all by-“ Toriel began to say before interrupting herself. “Wait, did you hear that?”

You heard what sounded like hopping in the distance.

“Oh no! I forgot that the Froggits like to play bridge over here on Tuesdays!” Toriel said in a panicked voice. “We’re going to have to hide you, and fast! Uh, quick! Under here!”

Without warning, Toriel lifted up her dress and forced you and your soul underneath it. Before you even knew what was happening, your face was already pressed up against the crotch of the goat woman’s black panties. The impact against her hidden muff caused Toriel to jump a little, but she quickly regained composure and shifted herself so you were facing her rear instead. Though it was dark inside her dress, you could still make out her short, fluffy tail sticking out over the back of her panties, as well as the outline of her curvaceous rear.

“Just stay under my tail and don’t make any noise, and I’m sure no one will notice you” Toriel said in a hushed tone. “Shh, here they come now”.

You couldn’t see what was happening from under Toriel’s dress, but you could hear the sound of something hopping its way into the room, followed by a small group of others doing the same thing. The sound of hopping continued to grow closer and closer until you heard whatever was making the noise stop just in front of Toriel.

“Ribbit” said a strange sounding voice from just outside Toriel’s skirt.  Even though it sounded a lot like a normal frog’s croak, you could somehow tell that whatever it was meant “Hello”.

“Hello to you too, Frogcine” said Toriel above you. “How are you doing this fine evening?”

“Ribbit, ribbit” said Frogcine, which translated to “Just fine, thanks. How about you?”

“Oh, you know, just doing my daily patrol of the outer ruins” Toriel replied nervously. “No humans today though. In fact, it actually felt like there were even more no humans there than usual!”

“Ribbit” said another voice, which translated to “Say, is it just me, or does your butt look a little bit bigger than usual today?”

“Heh, I don’t know what you’re talking about” Toriel said nervously as she reached back and discretely pressed your face deep into her squishy ass. You couldn’t help but be turned on by her enormous, fuzzy rear, but you managed to keep your heart from beating too loudly and giving yourself away.  

“Ribbit” the voice said again, which meant “No, it’s definitely bigger. You really should lay off the snails, Toriel”.

“Ribbit” said another voice, meaning “Yeah, my sister recently switched to slugs, and she was able to lose at least five pounds”.

“I’ll be sure to keep that in mind” Toriel said, laughing. “I really should get back home, though. See you girls later!”

“Ribbit” several people said at once, which translated to “Goodbye, Toriel”.

Toriel then moved forward unexpectedly, which almost caused you to trip and fall out from under her dress. You swiftly caught back up, however, and wrapped your arms around her waist to ensure that you didn’t fall behind again. This also gave you the benefit of returning your face to its comfy resting place against Toriel’s rear, though you were going to leave that detail out if she asked about it.

After walking for a few minutes, Toriel finally stopped and allowed you to exit from under her tail.

“It’s alright, child” she said as she tried to hide the blush on her face. “They’re gone now”.

The room you were now in was a very long and empty corridor. The only thing in it besides you and Toriel was a large stone pillar at the far end of the room.

“You have done very well thus far, but now it is time for your greatest challenge” Toriel explained. “I would like you to walk to the other end of this room by yourself. Forgive me for this”.

She then snapped her fingers and, in the blink of an eye, Toriel had completely disappeared. You were a little bit scared about being alone again, but the complete lack of any traps or obstacles in your way made the experience a lot less frightening. If anything, the entire ‘challenge’ felt incredibly patronizing.

After about a minute or so of walking, you finally made it to the pillar on the far side of the corridor. You were about to simply move onto the next room but stopped as Toriel stepped out in front of you from behind the pillar.

“Greetings, my child” the goat woman greeted with a smile on her face. “Do not worry, I did not leave you. I was just hiding over here the whole time. Thank you for trusting me”.

It annoyed you that she kept calling you a child over and over again, but you bit your tongue and didn’t say anything.

“This exercise was done in order test your independence, and you passed with flying colors” Toriel continued explaining. “I must attend to some business, and you must stay alone for a while. Please remain here, it’s dangerous to explore by yourself”.

You asked what you should do if the ‘Froggits’ from earlier come back through this room.

“Don’t worry, they should be playing bridge all night” Toriel replied. “Although, they might get done early… ah! I know!”

She then reached behind her back and took out an old looking cell phone, seemingly from nowhere, and handed it to you.

“Just hold nine to speed dial my number if you need anything” Toriel instructed. “I won’t be long, so be good, alright?”

You nodded in response and Toriel left the room through the doorway behind her, leaving you alone in the corridor with just the stone pillar and your beating soul.

Without anything better to do, you decided to sit down and lay your head against the pillar to try and take a nap with your soul resting comfortably in your hands.  The digital clock on your phone showed that it was about midnight now, and you were getting pretty tired.

However, your snooze was interrupted only a few minutes in by the sound of croaking right next to you, which caused you to jump a little in surprise.

Your eyes then opened to reveal a large woman with light green skin and dark green hair kneeling down next to you. She wasn’t as tall or as busty as Toriel, but she was still much bigger than you. She wasn’t wearing any clothes, which allowed you to see every inch of her slimy naked body. You could also see both her hands and her feet were webbed, and more closely resembled those of frogs than those of humans.

“Ribbit” croaked the Froggit, which meant something along the lines of “You’re a human, aren’t you?”

You quickly tried to think of a cover story, like that you were actually a teapot that learned how to walk and talk, but it was already too late. You had been discovered.

“Ribbit! Ribbit!” she said happily, which translated to “I knew Toriel was hiding something! A real life human! Now we finally have a chance of getting out of here!”

Remembering Toriel’s advice, you tried to change the subject by asking about The Underground’s stock market. This clearly didn’t work, however, as the Froggit stuck out its long tongue and delivered a strong lick directly to your floating heart.

Pain rushed up your spine as you felt the Froggit’s paralyzing magic begin to take over your body and soul. You begged the frog woman to let you go, but she kept licking at the heart anyways. It wasn’t long before you slumped to the floor, completely helpless.

“Ribbit, ribbit” the frog woman said proudly, which meant “Wow that was easier than I thought. You really got licked”.

You begged the Froggit to spare your life and your soul.

“Ribbit” she responded sadly, which meant “I’m sorry, but it has to be this way. I’ll try my best to make you enjoy it, though”.

She then sat down onto your chest and began undoing your belt. You could feel her slimy pussy soak through your shirt as she began tugging off your pants and underwear to reveal your flaccid cock.

“Ribbit, ribbit” croaked the Froggit, meaning “Wow, a boy’s penis. I’ve never seen one in real life before”.

It took a little struggling, but you managed to tell the Froggit that you actually consider yourself to be agender.

“Ribbit” she replied, which translated to “Sorry.  I guess that if I’m going to kill you, I might as well get your gender right”.

She then bent down and began taking your long dick into her mouth, which sent shivers of pleasure up your back. You tried to focus on something else to avoid becoming erect, but there was nothing you could do; the inside of her mouth felt too good. You could feel her long, dexterous tongue worship every inch of your growing prick. What her mouth lacked in warmth she made up for with enthusiasm, bobbing her head up and down on your dick at a nearly breakneck pace.

She could tell that you were reaching full hardness as your prick began leaking precum into her mouth, which she eagerly lapped up. Then, once she was done, the Froggit began wrapping her tongue all the way throbbing cock, all the way from the base to the top. The pressure on your prick was tighter than anything it had ever experienced before, and you couldn’t help but let out a small moan.

Your ecstasy only increased as she began to move her coiled tongue up and down your cock. You could feel every cold, slippery fold with every movement of her head. It didn’t take long for her blowjob to become too much, and you began firing shot after shot of warm cum into her mouth. It felt as if you were spraying an even greater amount than usual, which was confirmed as you saw the Froggit’s cheeks bulge from the pressure. As the incredible feeling of your orgasm finally began to subside, the world started to become hazy as you felt your soul begin to slipping out of your control.

A loud gulp informed you that the Froggit has successfully swallowed of your seed, but it was clear that she wasn’t finished with you yet.

“Ribbit” she said as she lifted herself off your chest, which meant something close to “I really hope you enjoyed that. I know it won’t matter soon, but I want to make your final moments as comfortable as I can”.

You informed her that you would be most comfortable alive, and as far away from her as possible.

“Ribbit” she said a she aligned her crotch with yours, which meant “I’m sorry, but it has to be this way”.

She then began to rub the lips of her pussy along your softening prick, which swiftly began to bring it back to life even as yours began slipping away. You couldn’t tell if the slime you felt on your cock was coming from her gaping cunt or from her naturally moist skin but, either way, your eager prick was soon lubed up and ready to enter her.

You could feel the Froggit’s bulbous fingers as they adjusted the angle of your prick before she lowered her hips and engulfed the entirety of your aching cock in one thrust.

“Ribbit!” she moaned, which translated roughly to “Ribbit!” in moan form.

She then began driving her hips up and down and swallowed your prick over and over again. You could feel the inside of her pussy massage the sides of  your dick, and the mouth of her womb kiss the top of its head.

“Ribbit! Ribbit!” she moaned as she grasped onto one of her nippleless breasts, meaning “Don’t worry, I’ll take good care of your kids after you’re gone. That way, you’ll live on in spirit!”

This provided little comfort as you found yourself hurtling towards your next orgasm already, and you could feel that this one would be your last. With one final grunt, you unleashed your load into the Froggit’s deepest depths and setting off a climax of her own. Soon, the world began to grow white as you felt your heart begin to break in half, and your life ended as another inside the Froggit began. The last thought that went through your head before you died was that you wished things had gone differently.



Save Loaded



The next thing you knew, you were suddenly back lying against the pillar you tried to take a nap on earlier. At first you thought your encounter with the Froggit was just a bad dream, but then you opened your eyes just in time to see her kneel down next to you.

“Ribbit” croaked the Froggit, which you already knew meant something along the lines of “You’re a human, aren’t you?”

You quickly stood up and began to panic, your mind racing at a million miles an hour to figure out what was going on.

“Ribbit! Ribb-!” she said happily, which translated to “I knew Toriel was hiding something! A real life human! Now we-”

The frog woman was cut short by your fist slamming into the side of her face. You had lashed out at her in your desperation to escape, hoping beyond hope that it would buy you enough time to escape the room before  you were captured and raped again.

Your punch did much more than just stun the woman, though; it sent her flying into the wall behind her. You looked down at your hand in confusion as the dust slowly began to clear from the impact. You didn’t feel any stronger than normal, and yet you had sent a woman almost double your size across the room with just one hit. You could recall from your earlier rape that she was a lot lighter than she looked, however.

Eventually she pried herself away from the wall and you put your fists back up into the air to try and defend yourself. But, instead of attacking you again like you expected, tears began to well up her eyes. Soon, she was practically crying her eyes out and ran out of the room, bawling. Guilt for what you had just done began to fill your body, and your soul began droop in the air next to you.

You followed the sound of sobbing for several rooms until you found the Froggit quietly crying to herself in a corner.

“Ribbit?” she asked in between sobs, which  meant “Are you here to finish the job?”

You shook your head ‘no’ in response.

“Ribbit? Ribbit ribbit ribbit” she said, meaning “Why not? It’s not like I was ever any good to anyone anyways. I’ve always been such a loser. I have no job, I suck at bridge, and now I can’t even beat a human child. The world would probably be better off without me anyways”.

Your soul twisted and convulsed next to you as storm of conflicting emotions began to well up inside you. On the one hand, she was clearly alone and in need, and you reflexively wanted to try and comfort her. But, on the other hand she just tried to- no, she DID just rape and kill you, so you were understandably still angry at her.

In the end, however, it all came down to a single choice; did you show mercy to her, or not?



A/N: Well, I hope you all enjoyed this first chapter. Please let me know what you thought about it in a review and please, if you have not already, buy Undertale. It is the single greatest video game I have ever played, and I guarantee you that you will not be disappointed.



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