#underswap gaster

After almost half a year of no "fun facts and did you know" series. It's time for more stuff about them

And to get a bit of fun, I'll be adding headcannons to some of the facts. Since just some facts wouldn't be enough.

Here's some of them (keep in mind though, the indented one is canon and one below them is headcanon ones):

Stars canonically can NOT have sugar whatsoever. That's because if he did, he's actually in a sugar rush and caused the house to float in temporary space with no gravity and give many facts of planets and science stuff.

And to sum it up, while he's in, Wingding would immediately take notes of Stars' universe out of curiosity and research (while also confused). Who knows that if they ever get out of the void, they somehow teleport to Outertale instead of their own homes. I think the reason why he's in the sugar rush was because Swap unknowingly put the sugar in Stars' drink and the tallest man in the team forgot to tell them about it.

B had heat at least once in a year and would run outside of the void to deal with it so he couldn't hurt the gang and hurt anomalies instead. And it's confirmed that the gang once did, but only to Fell and Swap ended up hurt.

But after the incident involved Swapfell, both Fell and Stars would take turns to silently look at B far away (mostly at home just to be safe bc B's TOO aggressive). Even though Swapfell is canonically weak and can't make B triggering his worst memories because B's blind (it's confirmed that Swapfell's triggering powers needed someone with sight based on here), it doesn't mean B notices his movements. The gang ESPECIALLY Fell needed to make sure that Swapfell didn't do bullshits on him.

After Swapfell's betrayal, Wingding is the most depressed out of them. I mean, who wouldn't since him and Swapfell are the same age and because they're the same person in a different universe. Stars not only makes him snapped out of it after Wingding distance himself from the gang, they're making sure he didn't do anything that's killing him.

There's also the time where Wingding wanted to go back to where they're together to the point that he's overworking himself to the limit to forget about Swapfell, but only for Wingding to think worse of the moments before disaster to the point that he's passed out in the middle of the experiment badly and alert Stars about it. Wingding ended up not waking up for days and sick afterwards, resulting Stars had to check ups on the gang alone with the help of Maestro and Swap.

That's all I can think of. And drop your headcanons though cause I wanna know too about the gang.

AUpril Day 2 - PASTRY

AU: Underswap

Characters: Muffet, Swap/Blue, Stretch, Gaster mentioned

Trigger warnings: tw past neglect, tw past abandonment, tw broken bones mentioned

Tags: Undertale aupril 2026, Blue is 10, Stretch is 5, Muffets 26, Gasters not in the picture anymore, Baking, adoption

Favourite typo: your sin sans

This takes place before they would know about Aus, so theres no way they would know to use nicknames (blue, stretch extra) which is why no nicknames are used.

~~~~~~~~~~~~~~~

Muffet was in the kitchen getting everything ready to start baking.

“Mommy?” A small voice called out.

Muffet quickly turned around, only to see Papyrus peeking his little head around the corner.

Muffet couldn’t help but giggle “huhuhu~ yes dearie? What is it?” She got down onto her knees to be at the tiny skeletons height.

The tiny skeleton slowly walked over to her. And opened his mouth only to close it again.

Open.

Close.

Open.

Close.

“Do you need something dearie?” Muffet asked quietly.

“I-. . . Um. . . Can. . . Can i . . .” Puffing up his shoulders and straightening his arms he yelled out. “CAN I HELP YOU!?”

Muffet was taken aback Papyrus was usually pretty shy, so him yelling like this was unusual.

Muffet smiled. “Help me with what dearie?” She had an idea of what he meant but she wanted him to have the bravery to say it himself.

“Can. . . I help you bake. .?” He asked sadly like she was going to say no.

“Hmm. . . I don’t know Papy, you’re still pretty little. . . And-“ Muffet paused when she saw Papyrus’s crushed face. He was leaning down a little with his hands nervously strung together, head low.

It had been two years since their father’s disappearance, finding him alone in waterfall, and then him promptly disowning his sons and their house to become some boat person.

Muffet still remembered finding the boys crying outside in the snow, how she took them in and gave them food, they had been starving for days.

She remembered the day they came home crying, how they found their dad, how he didn’t recognize them anymore.

How he had called them brats, told them to leave him alone forever. On that day, Muffet had taken them to the court and gotten legal custody of them.

Two years, now since that day. Papyrus had been 3 at the time, and was now 5 years old. He hardly remembered his dad, but there were still scars from that event that would never leave him.

Muffet sighed. “Sure, you can help me out dearie.”

Papyrus’s face lit up like stars, too bad he couldn’t make his eye lights be stars like Sans’s or your sure he would’ve by now.

“Re-really!? Yay!!” Picking Papyrus up, you walk over to the counter and show him all the baking you had to prepare.

“Okay.” Muffet started. “Why don’t we start with having you help me mix the dry ingredients together, okay dearie?”

“Okay!” Papy said excitedly, he was squirming in Muffets many arms, eager to get started.

Muffet moved things around on the countertop, making room for Papyrus, then put him down on the countertop.

Muffet grabbed flour, sugar, cocoa powder, baking powder and salt. Then grabbed the Appropriate measuring spoons for each item and laid them out.

“Ooooo! Cups, we can play the cup song-“

“Focus Papy, ahuhuhu~ we’re making spider cupcakes remember dearie?”

“Right, right! Hehe!” Papyrus clapped his hands together and wiggles his legs he couldn’t wait to get started.

“Ahuhuhu~ try to contain yourself dearie we wouldn’t wanna make a mess of the kitchen!” Muffet said absentmindedly not realizing her mistake.

Papyrus took this as a challenge, he decided to sit perfectly still. He’d be the best helper mommy had ever seen!! He wouldn’t let her down.

“Alright dearie! Now lets put in two cups of flour, one n 1/2 cups of sugar, 1/2 cup of cocoa powder and a pinch of salt with a teaspoon of baking powder.” Muffet claps two of her six arms together as she grabs measuring cups.

Papyrus smiled nervously not understanding a word she had said.

Wanting to save face he smiled and nodded. “Im ready!”

Muffet smiled deviously, this was gonna be fun. They started measuring and pouring into the bowl, Papy spilling some of the flour onto the counter.

“No!!” He whined.

“Its alright dearie-“

“But i wasn’t trying to spill it!!! I wasn’t, i wasn’t!” Papyrus started to cry a little.

“I know, i know- it’s okay-“ Muffet tried to sooth him.

“I wasn’t i promise!! I’ll do better!”

“Papy. . . You’re doing wonderfully, everyone makes spills sometimes, even i do!”

Papyrus stared at his mommy wide eyed. “You. . . You do. . ?” He sniffled.

“Mhm, i do dearie, everybody does. It’s not the end of the world my sweet honey bee.”

“Hehehe!” Papyrus giggled at the nickname. Even someone as small as him had a ferocious appetite for honey. (goggled at the nickname)

“Now. Shall we continue?” Muffet asked softly.

“Ya!” Papy said excitedly.

They mixed the rest of the ingredients together, stirring it together.

“Now we want to make sure these are stirred in very well!” She said with a smile on her face.

“Okie dokie!” Papyrus said with a grunt as he stirred as hard and carefully as he could. He was making a bit of a mess but Muffet paid no mind to it.

Once it was finished they moved onto the wet ingredients.

“Alrighty now dearie we shall need another bowl!” Papyrus quickly lifted up the other bowl beside him.

“Perfect dearie ahuhuhu~” She thought to herself on how adorable Papyrus was being and how she could just eat him up ahuhuhu~

Getting out the measuring cups again she was ready for the next step.

“For are wet ingredients we shall need half a cup of butter, 1 teaspoon of vanilla, two eggs, and 1 cup of milk!” Cheerfully she stated, leaning to her side a bit like an anime girl.

Paps giggled again, clapping his hands. “Let’s do it!”

“Yes, let’s do it.” She giggled back.

They poured all the wet ingredients into the bowl, even heating up the butter to add it in all nice and soft. Muffet held Papyrus’s hand when pouring so they didn’t spill this time.

Paps was pouty that mommy was helping him, but he relented and let her.

“Now dearie time to mix the ingredients, can you handle that? Ahuhuhu~?”

“Yes i can!” Papy said, grabbing the wooden spoon ready to mix!

Papy got to work mixing in the ingredients. It was chaos, stuff splattering onto his face and clothes. However a good chunk did stay in the bowl, which was impressive for a 5 year old.

When it was time to mix the wet ingredients and the dry ingredients together, Muffet added the crushed up spiders, then everything went wrong.

Papyrus had Accidentally knocked the bowl off the counter onto the floor spilling out.

“No!” Muffet yelled without thinking.

“Nononono-“ Papyrus screamed, nonono this was all going wrong he had already messed up once! now he completely ruined it. It was all ruined they would never make these cupcakes, she would never let him bake with her again, his dad was right he really was a brat.

An annoying selfish brat.

These were for mommy’s work.

And he ruined it.

He started to cry.

Muffet picked up the bowl, half the batter had spilled out but there was still enough left for some cupcakes. Not enough for the store though.

Muffet startled when she heard Papyrus crying.

“Oh dearie please don’t cry its okay-“

“Im sorryy!!!” Paps cried out, tears welling in his eyes. “I ruinedd it! I ruined everything!! Im sorryy!!”

“Papy everything is okay. We can still salvage this-“

“No we cant!! I spilled it all!! I ruined everything! Daddy’s hic right, i am a brat!!” Papyrus continued to sob into his hands. Muffet felt her heart stop, she thought Papyrus had forgotten about his dad, turns put she was wrong.

“No. . No Papy- Papyrus. You’re not. . Look at me.” Muffet puts the bowl down on the counter and wraps Papyrus up into her six arms.

Papyrus looks up at her with teary eyes.

“You are not a brat. I don’t know why your father forgot who you are. I don’t know why he told you you’re a brat. But listen to me. You are not a brat. Got it? You and your big brother are the best things that has ever happened to me!”

Papyrus nods slowly still sniffling.

“I am proud of you Papyrus, you’ve done a lot better than i could have ever hoped out of a 5 year old child.”

“But i ruined it-“

“No. This can be. . . Um. . . A test batch! Just a test batch for me, you and your big brother. Make sure we got the recipe right! Then i’ll make it for real after! It’ll be a little late but thats okay.”

Muffet smiled to herself the image of her two kids enjoying the cupcakes making her heart warm.

“A test batch?” Papyrus looked curious. “Yes! A test batch! Nyeheh! Fit for the mag.. the maganifint.. sans!”

“Magnificent, honeybee.” Correcting him softly.

“Maganificnt” Papyrus repeated.

“Close enough.” She booped his nose.

“Now then why don’t we finish this once and for all?” Muffet put papyrus back down on the counter clapping her hands together!

“Ya!!!”

Carefully pouring the cupcake mix into the trays, they ended up only having enough for 8 cupcakes when the recipe called for 16.

That was okay, 8 between 3 people was more than enough.

“Now time to put these in the oven! Which i already preheated to the correct temperature!” Muffet clapped her hands together.

“Ooooo, can i-“

“Im afraid your a little to young for this part dearie, maybe when your a bit older i don’t want you burning yourself.” She said as she put the tray in the oven.

“Oh. . . Okay.” Papyrus looked a little dejected but tried to hide it.

“Now we wait about an hour. . .” Muffet wiped some sweat off her brow.

“An hour!? Whys it take so long i want them now!!” Papyrus whined.

“Because silly bee it needs time to cook or it wont be edible. Ahuhuh~” Muffet put a hand to her mouth.

“I guesss.” He pouted, crossing his arms.

“But for right now we need to get all cleaned up.” She said with a smile.

“Can i help?” Papy asked shyly.

“You can go take a bath.” She giggled.

Papyrus suddenly looked down at himself and noticed he was covered in batter. “Oh! Okay! Bye bye mommy!”

“Bye bye dearie~ i’ll see you after your bath alright?” She picked him up and put him on the floor.

“Mhm!” Paps nodded as he ran off giggling to grab his bath toys.

Muffet sighed as she brushed her hands off on her apron. This would take awhile.

When Sans came back home from school, he was in a bad mood. The kids were teasing him again about his dad.

“Look it’s the loser whose dad abandoned him!”

“Haha who’s his new mommy again the freaky spider?”

“Haha what a loser I bet he has to eat spiders for dinner now every night!”

“Ewwww!!!”

He had gotten sent home early, he had hit one of the kids. they had made fun of his Mother and they had paid with a broken nose. Her food was to good to be insulted thank you very much!!

Ugh what was wrong with these people, they made fun of Paps too at the playgrounds, luckily he wasn’t in school today.

Sans knew it would only get worse once Paps was in primary school, sighing he walked up to the door, yellow paper explaining what happened in hand. He would be in so much trouble. . .

Ding dong.

He waited for the door to open, he didn’t have a key yet, not that he wasn’t responsible enough it was just that the ordered one hadn’t come in yet.

He heard someone scramble to the door, knowing it was Papyrus he quickly put on his mask.

The door swung open. “SANS!! WE MADE CUPCAKES!!” Papyrus screamed out happily.

“Wowie!! Really!? Wait we? You helped to!?” Sans was secretly impressed Muffet had let him help? They really were becoming like a family. . .

“Yes I did! Hehe! We made eight! I um. . . Spilt the batter.” Paps looked upset for a moment, Sans was about to cheer him up but Paps beat him to it.

“But Mommy said it could be a test run! So now we get to eat the cupcakes!”

Sans smiled wider, genuine. How adorable, how sweet Paps gets cupcakes like he deserves for his hard work.

“Sounds AMAZING Papy!! I the Magnificent Sans!! cannot wait to try these Magnificent cupcakes! made by my Magnificent bro!”

Sans knew he wouldn’t get any cupcakes not after punching a kid at school, but maybe he could sneak one before Mom saw what he did?

Papyrus grabbed him by the hand and dashed him over to the dinning room, where the delicious cupcakes were cooling off.

They smelled Amazing, Sans’s mouth watered. He wanted one so badly.

“Can we start now?” Sans asked Papyrus innocently.

“Yess!!!” Papyrus exclaimed happily. “We were waiting on you! I’ll go get mommy-“

“Papyrus wait-“ but he had already ran off to get Muffet. Oh well might as well start eating one before she arrives so he at least gets one.

Picking up one of the cupcakes Sans took a bite, it was sweet and savoury, these were perfect! He tried to avoid thinking about the spiders in them, or he’d fell bad for the poor bugs.

Sans was happily munching on a cupcake when he heard an indignant squeak.

“Sans!!” Papyrus stared agape. “You were supposed to wait for me!!”

Sans chuckled Mask slipping a bit. “Sorry bro-“ thats when he noticed Muffet’s arms crossed looking at him with a glare.

“Um. . . h-hi mom.” He said sheepishly, mask fully dropping.

“Why are you home at 11am?” She said with a devilish tone.

Sans started to say something then stopped, he shyly walked over to her and handed her the slip.

Papyrus stared at Sans confused, why did he look upset?

Muffet took the piece of paper and read it.

‘Dear Miss Muffet, your Son Sans is suspended from school for punching another child and breaking his nose. He will be allowed back in 2 weeks, sorry for the inconvenience.’

“What!?” Muffet looked over at Sans bewildered, she knew he was being bullied but she never thought it would escalate this far. Sans wasn’t a fighter type, didn’t he hate fighting?

“Im sorry- i never would’ve done it normally- but- they were making fun of you! I couldn’t just sit there and do nothing! I- i- . . .”

Papyrus looked between his Mom and Sans. What was written on that note? Who was making fun of mommy? He wanted to know damn it!!

Papyrus started trying to read the note, Muffet quickly put the paper in her pocket. Papyrus pouted crossing his arms, nobody noticed him. Sulking he sat down and just listened in picking at one of the cupcakes frosting.

“You- you punched a child cause they were making fun. . . Of me? Why?”

“I- you’ve done so much for us! We would be starving in the cold without you!! I promised id protect us! I couldn’t just- sit there hearing them make fun of your food! Your livelihood! Just cause there pricks who don’t understand your culture i-“

Muffet and Papyrus were both surprised by this, this wasn’t like Sans at all, he wanted everyone to get along and be happy sure. But he had never been a fighter. Not until recently.

“If protecting us means beating up some bullies then i’ll do it! I cant stand seeing you guys upset, being hurt or laughed at! It makes me so mad!” Sans bent down hands trembling looking like he was about to grab onto his head.

“Sans. . Sans! Breathe everything’s okay, no one is hurting us. Nobody is going to leave.”

Muffet knew what this was really about, Sans was trying to earn his ‘keep’ so to speak. Protecting the family in his eyes, was how he did that.

“You do not need to prove yourself to me, you are always loved here.”

“But dad said-“

“Who cares what your father said! He’s not here! But i am. I’m not going anywhere and unlike him i mean it.” She started moving towards him. Sans started to cry.

Muffet wiped his tears away. “Oh precious dearie, I’m not mad at you for punching that kid. Do what you need to survive, but don’t get caught next time alright? Ahuhuh~”

Sans was caught off guard. She was. . . Encouraging it?

“Your. . . Not gonna disown me. . ?” Sans looked baffled

“Never. Not in a billion years, now let’s have some cupcakes shall we~?”

“Yes!! Sans needs to have more cupcakes!” Papyrus suddenly shouted, surprising them both, they honestly forgot he was there.

“Mwuheheh! Yes the Magnificent Sans needs more of these epic cupcakes!!” Putting the mask back on he ran over to the table to finish his first cupcake.

Muffet smiled, yes it had been two years since their dad left, and yes it still held trauma in both small skeletons. But she would do her best to give them a happy life, without him.

Sitting down at the table she took a bite of a cupcake. It tasted perfect, Paps had really done a good job with these pastries. Maybe he could be a baker when he was older.

Well whatever the future held, she would be there with her kids.

She smiled as the kids play fight over a cupcake with orange frosting.

“Rawr!!” Sans growled.

“Eeek! Sansss!! You’re not a dragon!”

“I am now and i breathe fire!!” He put his arms in the air like teeth.

“Ahhh!! Hahah!” Papyrus giggled holding the cupcake away from him.

Yeah, they would be alright.

~~~~~~~~~~~~~~~

Hehehe how you like them Pastry’s hmm? If you enjoyed this fic let me know! Or else dragon sans will get ya!

Cant wait to post tomorrow’s fic pet, and read everyone else’s fics and drawings!

Time to get back to writing hehe if everything goes well i should stay a week ahead on prompts for the foreseeable future.

Check my pin post for my other Aupril fics!

Lyn would curse a whole lot in the house along with Fell. When Swap caught on and told them to stop cursing, Lyn acted all surprised and dramatically said, “Ooh no! How will I curse now~” But unlike Fell, she could just switch languages. She would just switch to Hungarian. Swap couldn’t understand it anyway, or at least that’s what she thought.

One time, while she was making a quick snack for herself in the kitchen, she cut herself with a knife. “Kurva anyád!” she hissed in a harsh, whispered tone, before Swap appeared behind her and took the knife away. He held her hand and used his healing magic on it. “No swearing,” he said with his usual smile, focused on her hand, while Lyn just stared in disbelief. He didn’t… no, he wouldn’t have known. Maybe he just knew when she was cursing based on the tone of her voice.

Later, after the other Gasters were fighting anomalies, Lyn got herself hurt. She yelped as she fell onto the cold ground, void, or whatever that black ground was. “Picsába!” she yelled, holding the arm that had been lashed at her. Suddenly, a loud scolding yell came from not far away, where Swap was fighting a different group of his counterparts. “LYN MIT MONDTAM A KÁROMKODÁSRÓL?”

Swap had basically learned Hungarian curse words and even some sentences just to scold Lyn if she cursed in that language again. He learned it just to tell her not to curse. Swap takes his no-cursing rule very seriously.

Now Lyn has to think of new ways to curse without Swap catching on. She wonders if she were to learn curse words in a different language, would Swap learn that language too just to scold her again?

Spoiler alert: yes, he would.

A/N: this gaster is based off the gaster gang version of underswap!gaster, gaster gang was made by @bun-bunmuse

“No… I couldn’t help but fall in love again.”

Swap, from the Gaster gang, feels something sharp and familiar pressing inside his head whenever he’s with Blindy, or when he spends time with the other Gasters.

Each time, it’s different. Each time, a small spark settles somewhere in his soul. It makes him question whether he’s falling in love again…

or if his soul and brain are just playing cruel jokes on him.

Especially after the divorce. Especially after everything that followed.

Because of that, he’s overly caring. Careful. Gentle in a way that almost hurts him.

And without realizing it, he starts catching feelings for the Gasters — not all at once, but slowly, through shared moments.

Each experience is different, yet all of them bring back that same missing spark of love he thought was gone for good.

For example, when he’s with Fell and they’re constantly arguing, the situation never really makes him feel good.

But deep down, it stirs something in him anyway. Something raw. Something ...alive?

With Outerfell, he turns into a complete fanboy, always hovering around him, always hugging him. There’s a strange comfort in it.

A warmth in his soul he didn’t know he still remembered.

When he looks after Wingdings’ health, reminding him to rest and not overwork himself, Swap finally feels useful again.

Like he matters. Like helping someone gives him a reason to exist. But when that care gets brushed off — when Wingdings doesn’t listen and ends up worse — the guilt crashes down on him.

Because now it feels like his fault. He didn’t help enough. He didn’t do the right thing. He did something wrong… again.

And that fear hits him all at once: he’s going to lose someone he cares about. Again.

He never realizes how much he cares until things go wrong.

Or when he’s with Blindy, and they end up cuddling together, he forgets how much he missed having someone close while he sleeps.

Someone to hold. Someone who stays.

And all those small feelings, those brief sparks he feels around the other Gasters — they’re pieces of something he’s been missing for so long.

Something he thought he’d never feel again after everything that happened.

Love.