Posted originally on the Archive_of_Our_Own at https://archiveofourown.org/
works/10980540.
  Rating:
      Explicit
  Archive Warning:
      Underage
  Category:
      M/M, Multi
  Fandom:
      Undertale_(Video_Game)
  Relationship:
      Papyrus/Sans_(Undertale), W._D._Gaster/Papyrus/Sans
  Character:
      Sans_(Undertale), Papyrus_(Undertale), W._D._Gaster, Unnamed_Monsters,
      Unnamed_humans, Mettaton_(Undertale), Asgore_Dreemurr
  Additional Tags:
      Conjoined_Twins, Conjoined_Twin_Sans_and_Papyrus, circus_AU, gaster_is_a
      creep, Rating_for_later_chapters, lots_of_headcanons, Sans_and_Papyrus_in
      a_dress, Sub_Sans, Dom_Papyrus, Dom_W._D._Gaster, creepy_gaster, Monsters
      were_never_trapped_underground, surface_AU
  Stats:
      Published: 2017-05-24 Chapters: 1/2 Words: 1658
****** Conjoined Love ******
by galaxyskeleton
Summary
     Sans and Papyrus are conjoined twins in a circus— and they tend to
     steal the show.
     The royal scientist has an interest in them.
Notes
     so here's an actual fic. i was planning for this to be a oneshot but
     it's getting kind of long so it'll be two or three chapters at most.
     this is heavily inspired by white_crayon and otherangela, please go
     check them out first! i did not come up with this au but i like it a
     lot and i just applied my own headcanons to it very heavily.
     also, i do not know very well how conjoined twins work! this was me
     working with my own knowledge and what i believe of sans and papyrus.
     i'd accept criticism though.
     enjoy!
  This work was inspired by
      Freak_like_me by othersin, On_my_sweet_sixteenth,_will_you_take_me_to_the
      circus? by othersin
Sans and Papyrus were an odd set of twins. The first reason being that they
were skeletons— the only skeletons anybody around seemed to know. Of all the
plentiful monsters, skeletons had been killed off the most in the war that
ended with some treaty of peace— many people had died, and ten, twenty times
more monsters turned to dust, but monsters and humans separated mostly
peacefully. Skeletons were strong, stocky and brilliant monsters— they had been
royals at one point, the family of  Serif  skeletons, however the two boys were
Sans Serifs , which was even more of an anomaly for how much smaller the family
was. The boys grew up without any skeletal influence.
The second is that the skeleton brothers were more of a skeleton and a half.
Conjoined at the waist, they had one set of legs and feet, shared a pelvis, and
had a strong spine that branched off into two separate torsos, one much shorter
than the other, and ending in two separate skulls, though the boys’ ribs were
somewhat braided together— each boy controlled one arm. Even past that, the two
were polar opposites. Sans was a bit more mature-acting, though he was rather
lazy and preferred to stay inside away from prying eyes. Papyrus, however, was
energetic and spontaneous. Both were logic-driven but Papyrus leaned closer to
his heart’s desire sometimes, and the two were a reckless pair. Yet for what an
anomaly they were, the boys were beautiful. Sans’ bones were more fragile,
thin, but still a breathtaking sight, especially against Papyrus’ stronger,
supportive ones. Papyrus could easily go through a day with Sans’ sleeping
skull against him. Papyrus’ skull was angular and attractive, and Sans’ more
round and feminine. Their spines met where they connected to the pelvis,
blending perfectly.
Not even the boys could distinguish how they walked— most of the time they were
perfectly mobile, but when they tried to think about who was actually
controlling them, they tended to metaphorically fall apart— they would stumble
and bicker. Bickering was very common for them.
The skeletons lived in a large moving circus of both monsters and humans,
consisting mostly of monsters. The ringmaster was like their father, a kind but
quirky human with just one leg who still got around fine. Sans and Papyrus
loved the tightrope and learned to show off their odd body— learned to flaunt
it and not hide. That was always more Papyrus’ thing while Sans would get a bit
embarrassed, shy away from the crowd, an endearing thing. They also doubled as
bickering comedians— the fighting and jokes were an act in itself. They were
one of the most popular acts in the show, and always had to be ready to
perform, and for them it was easy— all they really had to do was act like
themselves.
Recently they came to the grand  New Home , the enclosed kingdom of monsters.
The king himself was interested. He was invited as well as the royal scientist,
Doctor W.D. Gaster, who was especially intrigued by the physical anomalies such
as Sans and Papyrus. Even more exciting was that he was a  Serif  skeleton of
royal descent— another very rare monster. Of course he was very interested in
the boys from the start. The ringmaster had ushered them off into a traincar,
speaking with them diligently.
“Boys, you have to be on your best behavior,” he had said, “I know you’re just
seventeen but you have to act a bit— well just be a bit more mature, alright?
The royal scientist is awfully interested in you two. Your act will be a big
part of the show. Be good boys for me, okay?”
And now here they were, just before the show.
“Sans— Sans, look, calm down.”
“No!” Sans fumed. “I’m not— I’m not wearing a dress. No. That’s bullshit, we’ve
never worn a dress before. We’re  guys .”
Papyrus grit his teeth. “Stop being a child!” He said, “look, Metta made the
dress specifically—”
“Oh, Metta, Metta!” Sans said, clasping his hand together with Papyrus’ and
holding them against his chest, throwing his head back and faking a lovesick
tone, “Metta did this, Metta did that,  oh  we have to listen to Metta!”
“Shut up!” Papyrus hissed, pulling his hand over his brother’s mouth. “You’re
being ridiculous! Will you just listen to me?”
Sans pushed the hand away, glaring. “No. No, I won’t, because nobody’s gonna
like it anyway if we wear a  dress!!  Why would we—”
“ Sans! Papyrus! Are you two ready?”
“No!” Sans called back to the stylist, “and we’re not wearing that dress!”
The man entered the tent after peeking in to make sure they were decent. “Yeah
we are!” Papyrus exclaimed, “Sans is just being an absolute  child  about it!”
Mettaton or ‘Metta’ was one of the tailor and stylists of the circus. He
especially liked helping the skeleton boys, with the challenge that their odd
anatomy presented, and Papyrus had a liking to him, but Sans not too much. He
was a robotic ghost monster, and at the moment he sported a short black wig
that flipped up to show his mangled eye— it had been torn apart when he was
younger and he never could afford to fix such intricate technology. He held up
the dress to them. The torsos were both black with dark blue lacing up the back
and the skirt would fit down to their knees, a burnt orange with navy blue lace
for detail.
“You don’t like it?” He asked softly, one hand on his hip.
“You’re not guilting me into wearing that!” Sans hissed, “why did you make us a
dress of all things?”
Mettaton huffed. “Sans, did you even try it on?”
“No, I don’t—!”
“Hey.” Mettaton stuck his hand out, hovering it over the side of Sans’ head,
causing him to grow silent. He cupped the younger boy’s head and tilted it up.
“Sans, come on. Your brother seems to like it. Can you two please try it on for
me and if you still don’t like it, we’ll go with something else. Okay?”
Sans swallowed hard, unable to help as his face went blue at the close
proximity. “Okay,” he squeaked, and let out a small breath of relief as
Mettaton pulled away and draped the article of clothing over Papyrus’ arm.
“Thank you, Sans.”
The man left, quickly followed by heavy inhales from Sans, his hand running
over his face. “I hate him,” he said weakly, “why does he have to do that? He
always guilts me into deals.”
“Sans—” Papyrus started uncertainly, but the questioned skeleton shook his
head. “Let’s just try it on or whatever.
The dress, of course, fit them perfectly— Papyrus immediately rather liked it,
as the torso was tight-fitting but also easy to move around in, and the skirt
wasn’t prudish or inappropriate— a perfect length for the two. Sans simply
bunched his hand in the bottom and refused to give any input on it, cheeks
blotchy cyan.
When Mettaton returned, the complemented the two (“See, Sans? You look lovely”)
and the skeletons gave no verbal complaint, though Sans still held a sour,
embarrassed look.
“Sans, come on,” the stronger huffed. “Don’t be so whiny. Why are you acting
like this?” His questions were met with utter silence and he sighed.
Quite the oddity the two were.
 
The show was a success as always. The pair exits with a curtsy, two heads
bowing down as the audience laughs. Papyrus smiles at Sans, a beaming ray, and
his brother cannot help but smile back.
“I love you,” Papyrus says after they exit. “You always do so well—”
“Shut up, Paps, I love you too.”
Their bickering ended about halfway through their performance— it faded to a
stare there in the middle of the entire stage when Sans’ resolve truly broke.
After that, they instead moved to actual actions across a tightrope, where they
were just a bit above the highest seats. Papyrus had met eyes with the King
more than once.
“Yeah, well the doctor looked straight at  me ,” Sans declared. “I swear. He’s
only got one eyelight and it looked straight at me. It was really intense.”
 Papyrus’ expression became perplexed. “Intense? What do you mean, ‘intense?’”
“It just…  was . He was so focused.” Sans paused, and his voice died down to a
murmur. “I think he looked up our skirt.”
Papyrus would have shoved him if he could.
 “He did not! Be quiet!”
“Well  what else  do you expect when our crotch is open because of a stinkin’
dress?” Sans exclaimed, “we were literally exposed to everyone.”
Papyrus flushed, then looked away. “Okay, maybe so, but he’s never seen
anything like us. He’s probably really curious about us!!”
“Or he’s a creepy old man who—”
“ Sans!!  Stop being rude.”
The boys just had a bit of time to talk before they were ushered off, to change
into something more formal but light to speak to the royal scientist, and
perhaps let him have a glance of their body. Sans especially found it
uncomfortable, and even Papyrus was hesitant towards the idea, but he convinced
Sans himself that the doctor would just be curious.
They ended up wearing a button-up meant to make their torsos look a bit more
separate as well as dark jeans, gaining lots of ‘you clean up well’ comments.
Papyrus took them with pride, and Sans shied away from them.
“Come on, Sans.” Papyrus would have to push, “accept a compliment sometimes.
You look just as good as I do. We’re almost the same person.”
The ringmaster (also dressed up in his best, not the usual quirky purple-red
outfit he wore) was invited to meet the king as well, unlike them. The doctor
specifically asked to see Sans and Papyrus, insisting even more after the show.
They didn’t have much time to dwell on nerves. They were quickly ushered off.
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