#undertail vore

The cold never bothered you, but even given that this was a bit much. You were bundled in all the best thermal gear of course, being in the arctic required it, but couldn’t help the shiver as a particularly vicious gust threatened to throw your fluffy hood down. Ah well, get the equipment checked quick and you and Taylor could get back all that much sooner. 

Taylor, your previously mentioned research partner, was slightly ahead of you in the ankle deep snow as you both slowly shuffled towards the ice shelf that harbored the frigid water you two were studying. Coring ice and checking for fossils and chemical dating, monitoring water currents and other various data to guide the calculations required, all of it was rather dull. The crunching of numbers was more your taste, Taylor was the one who loved all their equipment. They each had names, in fact. They treated the machines like they were their kids. You might tease, but you were glad for the levity in what would normally be a tearjerkingly boring job. You didn’t appreciate their insistence to not go alone near as much, however. But you also couldn’t blame them.

After all, sirens were about.

There were precautions against their fabled charms, sure, but the thought of man-eaters being out was terrifying. So with Taylor you begrudgingly went. 

Taylor approached the mooring spot of one of their submersible probes, and activated the winch to bring it up for inspection. It had stopped sending data a few hours ago, which is what started your trip outside. To be honest, you weren’t fully sure what the probes should look like, but the mangled pile of scrap that game up on the end of the line was clearly not correct.

“No! They killed Trevor!” Taylor wailed.

“This was Trevor?” You asked.

“Yes! And he’s dead!”

“Clearly. We’ll need a whole new probe at this point. Better load this hunk of junk up.”

“Rest in peace, Trevor. You will be missed.”

Any funeral rites were interrupted when your proximity sensors went off. As precautions against sonic attacks (read as: siren song) you both were wearing noise cancelling headsets with communication links specifically between both of your headsets and the home base. You both also had sensors that would ping when something moving besides you two got within range, and you had a sinking feeling you knew what it was before you whipped your head around to find the offender. 

Yep, definitely a siren. 

It had the lower body of a spotted seal, but the torso of a skeleton was plopped where the neck should have been. Vibrant pink eyes were oddly hooded seductively at you two. Even deaf to it, you could tell by posture and movements it was singing to you. 

Nope, no thank you.

“Leave the scrap, we’ve gotta move!” You urge, pulling Taylor up by the arm. 

You both move as fast as possible back to the snowmobiles, luckily not too far away, and begin to book it. As you jet away, you scream over your shoulder “Not today, Pinky! Find something less sentient to eat, ya jerk!”

To your shock, the thing looks legitimately offended, and even blows a raspberry at you before it dives into the water.

Did it actually understand...?

You didn’t give it any more thought, instead flooring your snowmobile back to the warm, safe base. You didn’t want to be lunch, and were also pretty excited to feel your toes again.

-----

Repairing that damn probe took so much longer than it should have. But that was mostly because Pinky was very much Not Helpful™.   

Taylor made fun of you for naming the killer skelemer, but you solidly blamed their habit of naming everything rubbing off on you. Regardless, Pinky had become the thing’s title and at this point you were near certain it knew its name too. 

Pinky surfaced not too long after any attempts to retrieve, replace, or repair Trevor’s remains. You were always on guard duty while Taylor worked, so you were the one to spot it first. You’d raise the alarm and you and Taylor would scram, but it was alarming how quickly the mer picked up on what your tiny team was doing. It quickly figured out neither of you could hear their song, so it gave up on that and instead posed in what was probably supposed to be alluring poses, literally beckoning you to come closer. It eventually got nearly lewd.

The first time Pinky went fully sexual, you busted up laughing. He looked offended right up until you posed while channeling your best Jessica Rabbit on the back of Taylor’s snowmobile during your retreat. From that point, he seemed to take it as a challenge and almost seemed to be laughing along at his own ridiculousness. He also seemed to pick up on the meaning of your habitual flipping of the bird as you escaped inland and would return your one finger salute, or even rise up out of the water sometimes with the raised middle phalange the first thing to break the surface.

Ugh, you’d seen this thing too many times. You were personifying it.

It hadn’t ever gotten more than 100 yards off, barely in range of the proximity sensors. So your sightings were seconds each. You’d rather keep it that way.

Fate did not comply.

The day you finally got Trevor 2.0 ready to submerge was the day everything went wrong. You and Taylor lifted the equipment, shuffling towards the edge of the ice shelf to chuck the machine into the depths. Pinky had yet to be seen despite you two having been out here particularly long without disruption. Had it finally given up?

No, the sensor went off which startled both of you, enough so that the equipment was fumbled and ultimately dropped. Trevor 2.0 hitting the ice caused a chain reaction. Both of you stumbled back, Taylor luckily onto solid ice shelf, you less luckily onto rapidly cracking ice. You hit water, and shock made you instantly black out.

-----

Sans lazily went toward where the humans would be. Ever since wrecking the probe, they’d been out there daily. But while his plan for easy lunch didn’t work since they were somehow deaf so his song, he didn’t even mind at this point. Playing with the spunky human, or Brat as he thought of them, was a highlight to his day.

Originally he had tried to lure them other ways besides song, but their ability to sass back at him had gone from vexing to charming, the same way his usual insult for them became an affectionate moniker. As a reward for getting a good chuckle out of him the previous day, he’d decided to give them a little extra time unmolested.

Any plans went out the door when he saw Brat hit the water. 

The other human was flailing about on shore and froze when it saw him, but he paid it no mind. He instead dover underwater after Brat’s panicking form. He watched as shock made them gasp, the precious air they needed becoming a cloud of bubbles around their rapidly sinking body.

Forget plans, all thought went out of his head and a protective instinct he didn’t know he even had kicked into overdrive. He didn’t wanna eat them anymore, but apparently human was on the menu again. At least, in a way. He briefly surfaced, less than a moment and just long enough to flush the water out of his system to replace with air before he dove, snatching their eerily still form. He shoved their head into his mouth and gulped greedily, dragging their unresponsive frame into his body. He had to get them warm, and he was the warmest thing in the vicinity. The air in his belly would let them breathe, and the warmth of his magic would keep hypothermia at bay.

Once they were down, he panted with exertion, feeling their body through his own. 

...SHIT.

The hell did he do now?

-----

You woke slowly, not knowing where you were.

Then you remembered and suddenly waking up was very fast. Still didn’t know where you were though. You flailed around in surprise, finding everything rather squishy, wet, and ...pink?

“human?”

“Huh- what?!” You cried in response to the sudden voice, falling backwards and sliding to the bottom of this weird rounded space you were in.

“delta, i’m not used to shit moving around in there like that. dunno how i feel about that yet.”

“where am i?” panick straining your voice up an octave.

“uh, currently inside a siren. in neither a food way or a fun way, if that helps.” He said, blandly.

“PINKY?!”

“that’s usually what you call me, among insults of various quality and originality. ‘pink tailed prick’ was always my favorite.”

You’ve somewhat realized you’re in his gut now, and a quick once over of your body reveals that it’s intact, if damp. “....why am I not dead?” 

“i already said it wasn’t in a food way. you nearly drowned, don’t you remember?”

Crap, now you did. “The question stands.”

“fair. easy answer though; i begrudgingly like you, brat.”

“I’m a brat? You tried eating me- wait, did eat me!” You clap your hands over your traitorous smart mouth, god please don’t piss off the thing that can easily kill you if he had a mind to!

“well, i didn’t. not for lack of trying, though. and you’re still not food, you’re actually safer in there then out here. even i know you’d freeze to death if i just let you out on shore. you need to be dry, which isn’t really attainable for a mer.”

“...oh.” You can’t really object to the logic, even if your brain were in a place to.

“yeah. i did try to bring you back. other one tried to shoot me.”

“Damn, Taylor has shit aim.”

“they do. which leads us to now.”

“Oh... the ‘how the hell do we get me out’ phase.”

“yeah. and at this point without death. if you’re going to be making such a drastic impact on my impeccable figure for this long, it’d better not be in vain.”

“Excuse me Princess!” you guffaw, tone dripping sarcasm.

“sans.”

That stumped you. “Come again?”

“my name. it’s sans.”

“Oh. Well, I’m y/n.”

“well, y/n, you’re stuck in there until we find a way to get you back on dry land without near immediate hypothermia. so get comfy, because we’re sleeping now. even if i do look pregnant, i need beauty rest.”

“Oh. Uh. Guess I can’t complain. And uh... thanks for the lack of murder.”

He hums in reply, movement finally ceasing.

You slide into a maintainable, comfortable position and finally take in your surroundings, since you’ll be stuck here awhile. The walls do softly glow pink as you’d initially seen. Less obviously, they also have a subtly wavy texture, and a bouncy give almost like a waterbed. The walls are slick and frictionless, but don’t appear to leave slime on your questing hands. 

“that feels nice. feel free to keep that up.” sans interrupts your exploration.

There’s a brief flare of guilt before you take his advice and keep playing with the plush walls, as if pawing will grant you extra knowledge.

You don’t really remember falling asleep, but apparently you did. The soft sounds of his body around you make excellent white noise apparently.

-----

It had been days. Inside a siren’s belly. What is your life?

It was weird, but not too bad without the death to go along with it.

Sans encouraged you to play with he odd texture of his magic, but that got old after awhile. You would say however, that you were extremely comfortable. The walls had a lovely give, and tended to mold to your body in whatever position you took due to their plush nature. They even moved in a soft undulating pattern, which felt kind of like a massage. Oddly, you had gotten used to this enough to almost enjoy it.

Then you were doused with liquid magic. Again.

“Dammit, warn me!” You cried, wiping the pink glow out of your eyes.

“why would i? that’s so much less fun.”

“Pink tailed Prick.” You muttered.

“ah, my favorite title.”

-----

As nice as having a constant companion and warm weight inside was, he was at his wits end with this arrangement. Honestly not even because of y/n. They could come back to visit his gut again after this whole thing was over as far as he was concerned, but they other one was incredibly dense. 

The perceived loss of their companion really made it impossible to break through. Especially since they couldn’t hear him, and wouldn’t get close enough for him to get the headphones (which y/n told him were what made them immune to song) off. If he charmed them, the violence would stop long enough to prove y/n was ok. But lack of communication was a big issue here. Of course, the water had rendered y/n’s pair defunct.

Y/n appeared to have adapted to their space decently too, they didn’t struggle and once he was used to it their readjustments and stretches felt divine inside. They were bewildered by the fact that his magic could sustain them, meaning they didn’t have to eat as long as he intended to care for them. Them playing with the liquid magic his body converted his actual food to was hilarious, if maybe gross under other circumstances. 

He was going to miss his internal companion desperately. 

But that wasn’t the goal for now. Y/n came up with had to be plan H (he’d lost track of where they were in the alphabet by now) which was risky but the best shot they had yet. He’d just unzip on shore and show Taylor that y/n was ok. That meant that his human was risking hypothermia, and he would be in no position to bail if Taylor shot. (They were a bad shot, but that wasn’t a risk he was thrilled with.)

He didn’t really like this plan, but he hauled himself up out of the water by where Taylor would be sure to patrol, and waited for the human to arrive.

Eventually, an indignant “You bastard!” heralded the misguided human’s arrival. A bang indicated a gunshot, but no bullet whizzed by. Wow. Strormtrooper level bad aim, Taylor.

He turned to face them, then raked a finger down his belly, letting y/n throw their damp top half out into the frigid air. “TAYLOR, STOP!” they screamed, waving their hands in a ceasefire gesture.

Taylor either panicked or didn’t see, firing another shot. y/n screamed, pulling their now bleeding forearm close to themself. 

Sans reached a hand down, healing magic already summoned and tending to the new hole y/n had been gifted.

“that’s it, this didn’t work. get back in, we’re out.” Sans growled.

“W-wait! N-N-” y/n protested, blue lips and chattering voice making it difficult.

Sans was about ready to shove them in himself when Taylor called in utter shock “Wait... y/n?!”

Taylor stumbled forward a step or two, grip on their gun slack.

Thank Delta, this was the opening he needed! He used his magic to rip off their damn headphones, and before they could reorient their grip on their gun, he began to sing. With the charm in place, they could finally talk.

He also got to eat y/n again now, which was another bonus.

-----

You strode confidently to the water with Taylor beside you, going to check on Trevor 2.0 like normal. Most things were back to normal, but what wasn’t was far more interesting.

You got three things from the ordeal in the end, and they were as follows:

One, your hair was now pink. Prolonged exposure to Sans’ magic had affected your hair’s natural pigmentation, and there was no indication as to whether it was permanent or not. Eh, at least you’d save on hair dye.

Two, you got a scar. Taylor was endlessly sorry for it, but the bullet hole had left a definite mark on your forearm. Had to think of a cover story for that before shipping home. That was concern for later, though.

Three, you got a new friend or constant pest depending on how you felt at the given moment. The smile that broke on your face at seeing the familiar glow beneath the frigid surface of the water said you were currently leaning friend. 

Sans chilled with you while Taylor did their thing, Taylor also chipping in on conversation as they worked. The typical flow was interrupted when Sans’ belly growled.

“Too lazy to hunt again?” You asked.

Sans shrugged. “guilty as charged.”

“Just go, don’t do your usual beat around the bush thing.” Taylor butted in.

“Hey! I didn’t even do anything!” You groused.

They raised a brow at you, smiling mockingly. “You brought extra clothes.”

“...shut up.”

Sans and Taylor both laughed at you.

From his spot in the water, Sans looked up at you and said “i’m game if you are.”

You hesitated.

“Just go, I’ll have dinner ready by dark. I can get back to base on my own.” Taylor said, retreating to their snowmobile. 

You turned to Sans, who wordlessly opened his mouth wide and waited.