When everyone prepared to migrate to The Surface, the then-Sans thought that it’s time to leave his past behind.

He doesn’t know what compelled him to make that decision. He had all the capabilities and resources to make a copy of his secret lab and move everything there. Yet, he chose to neglect that possibility.

Was it hope? Was it laziness? Or was it merely whimsy?

Five years later, the owner returned with a different alias. The lab may not have changed… but he certainly did.

The Phantom floated into view, curiously inspecting every corner of the hidden laboratory. “Wowie! I never knew you had a hideout like this! What did you do here?”

“I don’t remember anymore,” Dust looked towards the curtain. “I remember dumping that broken down machine over there. Found it on top of the garbage pile one day. Felt like it’s something special. Can’t figure out how to fix it though.”

“Does it matter?”

“Depends. It may or may not be relevant to what I’m looking for. First, I need to find my way to New Home. Get to the root of the problem, y’know.”

“What is this ‘root’ anyway? You’re being annoyingly vague, as usual.”

“Papyrus told me to find him ‘in the gap between realities', 'in the realm of dreams’. We’re supposed to have a common memory over this, yet I don’t remember any such thing.”

Dust climbed up the stairs to the exit and used his silver key, tarnished black from age and neglect. In the back of his mind, he thought the object reflected his heart.

He tried to turn the knob… but it refused to budge. There’s a strange elastic resistance whenever he tried to twist the key.

“…This ain’t ice,” he commented. “More like a rubber band. Or… a vine…”

Realizing what may lay ahead, Dust withdrew the key and carefully stepped away from the door.

“I think I need to use a shortcut.”

The Phantom then asked: “How’d you know that it’s safe to teleport? One wrong move and you might find yourself in a dusty pickle.”

“Oh, I’m not using that kind of a ‘shortcut’. This one is much more mundane.”

With telekinesis, Dust pulled down a section of the ceiling. A rope ladder rolled out from a hatch.

Amazed, The Phantom exclaimed: “You had this all the while?!”

“Yup. Don’t like to use it, though. As you can imagine, it requires quite a bit of effort.”

And so, he grabbed the ladder. Rope-types were easier to hide and maintain, but they have an annoying habit of wobbling.

Up, up, and up he climbed. For some strange reason, it wasn’t as tiring as he remembered. Perhaps his roughened lifestyle built some stamina into his bones.

At the very top, Dust emerged from the corner of his former bedroom. Once upon a time, his bed covered up the exit.

Against the soft cave-lights of Snowdin, the shadow of thorny briars cast against the wall. The invasive vine had busted through the window. Ice, snow and thorns encrusted the interiors of his former dwelling.

Fortunately, the balcony wasn’t blocked. Dust stepped out there to take a good look of what had become of Snowdin.

How the town had changed. Briars choked the buildings, crawling out of windows and punching holes in places where they shouldn’t be. Heavy snow also blanketed everything, causing some of the rooftops to collapse from the sheer amount of weight. A lack of maintenance only added to the fragility of the broken buildings.

“Dammit,” Dust cursed under his breath. “The briars have infested the whole Underground.”

“Is that a problem?”

“Yes. A deadly problem. I’m treading on thin ice here.”

From there, he teleported down to safe ground and started zipping from clearing to clearing. Navigating the town without touching the briars was a maze in itself. He didn’t want to risk tripping any alarms that the bratty flower had laid out.

Soon, he stood before the entrance to The Ruins. The original door was smashed down by a choking amount of thorns, completely plugging up the entrance.

“Why the detour?” The Phantom asked back. “Isn’t this the opposite direction of New Home?”

“I needed to confirm if the alternative exit was available for use. Looks like I’m out of luck. Welp, off to check Waterfall.”

For that, Dust doubled back through Snowdin Town. Midway down the main road, he stopped in front of a particular establishment, gazing with longing eyes.

That place used to be Grillby’s bar. Although the signboard was long gone, he still recognized the location.

The Phantom commented, “You really loved that place, huh? Why? The food there was always so greasy…”

“The bar’s owner was a good man. Relaxing atmosphere too. Helps forget the troubles around you.”

“Do you miss it?”

“Always.”

He shook off the nostalgia to trudge forward. The sooner he leaves Snowdin, the better. That’s what he told himself.

He arrived at the cave that separated the icy cold from the warm humidity. Waterfall should be right ahead. But…

“W-what the hell?” he muttered.

…The area ahead had become completely submerged. Dams of briars had choked the rivers, causing the water to accumulate and stall. Algae had bloomed in the stagnant water, tainting it a sickly green. Nevermind the stench.

Rubbing his forehead, he grumbled, “Great, Waterfall has become Waterfull.”

In which The Phantom asked, “Are we going to swim? I’m positive skeletons can’t drown.”

“Nope, not touching the water if I can help it. I don’t think this case is waterproof. Losing my tools to wetness would just ruin the whole plan.”

Irritated, the ghost started to whine. “So what do we do now? We can’t do this, we can’t do that! It’s so frustrating!”

“Come, follow me,” he winked, “I think I know a shortcut.”

“Weren’t you already using shortcuts? You were teleporting all over the place!”

“Oh, I’m not using that kind of a ‘shortcut’. This one is much more fantastical.”

They backtracked a little bit, heading towards an old sentry point. Back in the good old days, Undyne used to complain about repurposing this defensive outpost into a shop.

Right behind the stall was a shadowy portal with a water-like surface. It’s been sitting there out in the open for as long as Dust remembered, yet no other monster was able to see it.

Using that shortcut brought him straight to his Hotland hotdog stand. Dust stood at the edge of a cliff. He was certain that this used to be a road.

Not even the heat, possible toxic fumes, and blistering magma could stop the nightmarish briars from overrunning the place. It appeared that they had drilled through whole sections of Hotland. The once connected pathways had become leaning pillars of broken rock, standing in the lava by their lonesome amongst the fire-defying plants.

Alphys’ Lab… ceased to exist. The site where it once proudly stood embraced the primordial liquid.

Dust said, “Ashes to ashes, dust to dust. The Lab was built from minerals extracted from igneous rock. It wouldn’t surprise me if it returned to its origin.”

The Phantom rubbed his chin, “Is nobody going to question the fact that those gigantic thorns are not burning or melting? I thought all plant-life was flammable.”

“Those same thorns survived a military air-strike, bro.”

“That… that’s a good point.”

“Either way, Hotland isn’t my goal. I just hope that the next shortcut isn’t compromised.”

The hidden portal in question wasn’t very far away. Dust counted his lucky stars that nothing happened to it.

One hop later, he stepped into New Home: the former capital of Monsterkind.

A still, silent air hung over the grey, hollow city. Every building here used to house life. Bachelors, couples, families, widows, widowers, orphans…

They’re all gone now.

For some reason, the briars didn’t infest New Home. Dust saw some around the edges of the city, but most concentrated on the main road towards Asgore’s castle. He began to wonder if the mastermind could only focus his efforts in familiar places.

That’s a mystery for another day. In the meantime, he must search for his final destination. Dust teleported to a high vantage point and started scouting.

He muttered to himself about the possible landmarks, occasionally checking the cave ceiling over his head for a specific formation of rocks. “It should be between the church, a small fountain, and a burger joint… Nope… not here…. Not here either…”

The sharp, pointed rooftop of the church caught his eye. It shouldn’t be far from that spot.

“Getting closer…”

At last, he found what he was looking for. Right beneath the brightest star in the undersky stood a building just like any other: a humble apartment with a flat roof.

One zip later, and his boot touched the concrete surface. Confident that he had found what he was looking for, Dust descended a stairwell into a hallway filled with several apartment doors. He was looking for the first one on the left. No one would ever return, so he destroyed the locks without hesitation. Didn’t need to care about preserving property.

“Here we are, bro. Welcome to our childhood home.”

“Oh?!” The Phantom floated around, checking out the space with great curiosity. “It’s so… so… different? Why can’t I recognize anything?”

“The house was sold to someone else when we moved to Snowdin. But how it looks doesn’t matter. All I need is the location.”

Dust set the metal transport case down and stretched his shoulders. “Time to get to work.”

He began unpacking the contents. First, he took out an electronic tablet and a large lithium battery. The items seemed to be at least five years old. He wondered if Anya was being frugal, or if production of advanced electronics stopped due to The Calamity.

After that, he laid out the spell scroll prepared by the Willowherb Society. It’s more complex than the ancient version, taking into account the need to process a new factor: sound.

And finally, the catalyst: Papyrus’ scarf, the genuine article, still carrying some of the original owner’s dust.

The Phantom crossed his arms as he inspected the setup before him. Skeptical, he questioned: “Are you sure she’s not conning you, Sans? This sounds like some storybook magic.”

“It’s all about vibrations, bro. Long story short, the theory checks out. We’ll see if it actually works.”

“Fine. Then, do you know where you want to start?” the ghost asked. “I don’t think your batteries can last for years and years.”

“My babybone days. I… I vaguely remember getting into trouble with some adults. Then, I stopped going to the regular nurseries. I’d like to know why.”

Scroll, activate. The magic circle started to shine, projecting holographic images into the empty living room and unfolding the scarf’s story.

A long, long time ago, there lived a skeleton couple. The husband bore amicable good looks, while his wife was an elegant beauty.

The Phantom gasped in surprise. “That man looks just like… me!”

“Heh,” Dust smirked. “That’s our Dad. I will always remember him as a calmer version of Papyrus. His name was Times Roman.”

Back then, the scarf was still whole, its beauty matching its owner. “See the lady? That’s Mom. Helvetica. Y’know, I still can’t believe I’m her son. Look at me, short and dumpy. Look at her, tall and elegant.”

“But she has the same face-type as you. More flesh than bone. And I bet you’ll look dashing if you dress properly for once!”

“Heh. You got a point.”

The husband sat beside his wife. “The holidays are starting, Helvi,” he said. “Do you have anything in mind?”

“I think I want to try fan-dancing again, Roman,” she replied. “It’s been too long since I’ve done so. My bones have stiffened from working at the school cafeteria. Figured I could make up for lost time and regain what I’ve lost. But… what if I can’t?”

“Whether you’re fan-dancing or not, you’ll always be the most beautiful woman in my life.” The husband smooched her on the cheek, smiling warmly. “Why don’t we have a little tango in the bedroom to prepare?”

“Right now?”

“If it improves your mood. We can even do it right here~”

The moment his parents kissed passionately, Dust halted the playback. “Okay. That was way too much unnecessary information. At least the sound is working.”

The Phantom blinked a few times before asking: “Sans, how could anyone do the tango in that tiny bedroom? There’s not enough space. Wait… does this have something to do with making babies?”

An answer, denied. “Moooving on.”

Dust finetuned the spell to fast forward a few months at a time, hoping to catch a glimpse of a clue to his missing memories.

He expected to see more of his parents, maybe even himself…

…Instead an unpleasant ‘thing’ stood amongst the family .

A white abominable entity, ever flowing, ever churning, stood in the middle of the living room.

It twisted. Shredded. Rippled. Shifted. Yet, it never fell apart.

Dust clutched his head in pain. Shockwaves of sharpness zapped back and forth within his skull. The mere sight of this abomination was like staring into a glaring noonday sun at the height of Summer. Searing. Blinding.

Then it attempted to initiate speech. ‘Attempt’, emphasized. What came out of the creature was nothing but screeches and gurgles, scratching and shrieking.

Disgusting. Utterly disgusting. That thing was an affront to his senses. Its mere existence threatened to rip reality apart.

Dust muttered, “What… what the actual fuck even is that thing…?”

The Phantom asked, “Sans? You said some really dirty words there. That’s so unlike you. Are you alright?”

“Can’t you see it?” Pointing towards the abomination, he said, “It’s standing right there. God, my stomach is attempting to eject upwards just looking at it.”

“No. There’s absolutely nothing there. I only see Mom, Dad, and a babybone. I think you’re that child.”

That was a curious note. Dust felt rather relieved. “Huh. I’m glad you don’t have to suffer the same torture.”

For his own health and sanity, Dust moved his focus away from the creature and toward his younger self. It seemed that the aches subsided as long as he didn’t stare directly at the offending entity.

Little toddler Sans sat on the floor, solving a complex puzzle cube. It was the kind that would stump adults. Beneath that wide, cheeky grin was a genius brain firing all its cylinders. When the child solved the puzzle, he let out a high-pitched ‘Yay!’ and proudly showed his handiwork to his mother.

“You’re such a clever boy!” Helvetica praised her son as she picked him up. After putting the puzzle aside, she began bouncing the boy on her knee. The toddler loved the illusion of riding a galloping steed.

All the while, that thing appeared to be observing the toddler. It started to speak in ear-grating screeches again, seemingly expressing a form of curious interest.

Times Roman replied like a normal person would. “We found this out just a couple of days ago, when I bought that puzzle box for myself. Sans solved it before I even got a try! If only he’d behaved better at the nursery…”

More screeches and scratches. The spell was unable to render anything intelligible.

“Well… yes. He kept pranking the other kids and made them cry. I don’t know what’s going on with him, [REDACTED]. I thought monster children don’t become naughty until they’re six years old. But… but Sans is only three. And you know, he already was a handful before this! Did you remember the time when he poured ketchup all over himself?!”

Not even that entity’s name could be mentioned, it seemed. Dust observed a rather lengthy pause in the middle of Roman’s speech. Curious. It had to be a person, he thought. Otherwise, his father wouldn’t be having an intelligent conversation.

After the glitched one spoke in reply, the father started to frown in concern. “…What? I thought necromancers are a myth. You can’t be serious about us skeletons descending from humans! I mean, that’s like saying horse monsters descended from actual horses. Though I don’t know what a horse actually looks like…”

The mysterious being continued to persuade. Despite the parents’ skepticism, they weren’t entirely dissuaded either.

“Roman,” said the mother, “If what [REDACTED] says is true, the usual nurseries aren’t equipped to handle our son. He needs a different approach.”

Turning to the figure, she said: “You may take him under your wing. My husband and I will need some time to discuss our terms, however. Is that alright?”

The entity… agreed.

The spell suddenly glowed brighter than usual. Dust felt a slip on his grip of the magic, as if someone yanked the controls away from him.

However, The Phantom didn’t respond or react. Perhaps he thought that it was all part of the plan? In order to not alarm the ghostly brother, Dust played it cool, pretending that this new development was of his own volition.

Days, months, years within the childhood home zoomed past like a tape on fast-forward. As abruptly as it began, it stopped. On that day, the unknown blob appeared to be wrapping bandages around Helvetica’s right arm. Roman looked on with great worry.

“What just happened?” asked the distraught father. “Helvi found Sans crying on the ground in pain. When she tried to pick him up, some strange magic burned her arm! Then he… he… Teleported! I saw him hopping across the neighbouring roofs before he straight up vanished! The Royal Guard have yet to find him. What if he’s stuck somewhere? Or dangling over the Hotland magma???”

In contrast with the father’s panic, the entity was outright elated. Each sore sound and nondescript action somehow conveyed joyous excitement beyond comprehension.

Roman was both confused and offended. “Awakening? The Seer’s Eye? [REDACTED], you’re not making any sense! My wife is injured and my son is missing! How is that a good thing???”

Someone started knocking on the door. The image of Roman hurried over to answer it. Not long after, he returned with relief on his face.

“The Royal Guards have found Sans!” he exclaimed, “They took him to the hospital. C’mon, Helvi. We should get your wounds checked out too.”

His parents and the glitched one left the house as soon as possible. The spell wouldn't render anything outside of its designated field.

Shocked, Dust muttered: “That… that was real? I thought it was just a nightmare.”

“Hmmmm?” The Phantom crossed his hands. “Care to explain?”

“I think I was about seven years old? Maybe eight? I was playing with a ball on the rooftop. Then, I had a massive headache. Thought my skull was gonna split into two. Next thing I knew, I woke up in a hospital bed.”

“What about Mom’s injury?”

“She told me that she got it from a workplace accident. Some mishap with hot frying oil.” Dust knocked his own skull in regretful frustration. “Dammit. I can’t believe I fell for that lie.”

The ghost sighed in a disappointed tone. “I guess our lying habits had to come from somewhere. We’re never truly honest with each other, are we?”

That rubbed Dust the wrong way. “Hey, keep Mom out of this. She’s not here to defend herself anymore.”

“That doesn’t mean we didn’t inherit it.”

“Fine.” Not in the mood to argue, the elder brother asked: “What do you suggest then?”

And so The Phantom cheerfully demanded: “Look for more information about The Great Papyrus-- I mean me! More about me and less about you. I want to see what happened when I was a babybones, nyeh heh heh!”

“Alright, alright. Maybe that would turn up more clues about our mystery man too.”

Dust moved the spell’s timescale forward to when he was about nine years old. Dear mother was pregnant with her second son. Dressed in her maternity clothes, she caressed her large belly in deep concern.

Roman just came home with a bag of groceries. “Helvi? How are you feeling?”

“Physically, I’m fine. But… I’m worried about our unborn boy.”

“Because of the ultrasound?”

“Yes,” Helvetica replied, “Do you still remember what happened to Sans? When his left eye turned cyan? Apparently it’s some kind of a recessive power of our kind. The chances were supposed to be low, yet somehow we’ve gotten that gene twice! Would our second son experience the same agony and terror?”

Dear father placed the groceries on the table and sat beside his wife. Holding her hand, he reassured, “Don’t worry. He’s making a special spell to make sure that accident doesn’t happen again.”

“I don’t think it’s that simple. Didn’t you notice, Roman? How gleeful [REDACTED] looked? He kept saying that a bright future awaits the second one. Maybe that child will even become the saviour of the Underground.”

“The one who has seen the Surface… I don’t know why our child would be ‘The Angel of Prophecy’. Then again, [REDACTED] is known to go into mad science rambles. Well Helvi, I think it’s all talk and no harm. He’s quirky like that.”

“No harm, you say?” Helvetica grumbled cynically. “Maybe he just didn’t have the chance to inflict any harm to anyone. I fear if this keeps up, we’ll get swept up by his delusions.”

“D-dear, there’s no need to be so pessimistic. What if we look at this from another angle? Imagine one day, our second son grows up into The Underground’s Number 1 Hero! I can picture it now, our boy standing tall… and everyone will call him ‘The Great Papyrus’! Has a nice ring to it, right?”

“Well… I suppose. You do have a point.”

‘Hero’. Papyrus always dreamed of being a hero. All the while, Dust thought he was inspired by Captain Undyne’s bravery. What if the idea was instilled long before that?

The Phantom started freaking out, flying around the room with excitement. “I was right all along! Destiny! Fame! Glory! All mine! Nyeh heh heh heh heh heh!!!”

While the ghost celebrated, the reveal bothered Dust: Why didn’t Papyrus become the hero then? What changed, and when?

He glanced at the estimated battery life. It’s almost gone: there’s only enough energy for one more slice of history. He’s got to act fast.

A flash of inspiration flipped through his mind. It took the shape of a certain black book. Deceivingly simple, yet its knowledge was invaluable.

Without asking for any further input from The Phantom, Dust searched the scarf’s memories for the moment he came to possess the Book of Vanquishing.

The toddler had grown up into a teenager, carrying a responsibility beyond his age. He had a little brother to raise. By this point, his parents had long become dust. His mother’s red scarf -- her heirloom -- was passed down to her eldest child.

Irritated, the teen snapped at the mysterious entity. “Look, I found that book in the Royal Library. I thought it was just some edgy fantasy. How am I supposed to know it’s not make-believe?”

And then, the entity passed a thicker, heavier, and taller red tome into young Sans’ hands.

Dust immediately recognized the cover: it was none other than The Book of Curses.

However, the teenage version of himself had yet to know this terrible truth. The boy asked: “…You want me to verify the contents? I guess if they use the same terminology, they must belong to the same set.”

So the boy began reading through the pages, making commentary along the way, “…The Delta Rune? No. It’s arranged differently. Weird. Um, moving on… The Damned? Yeah. The black book warned about them.”

“Uh… The Crimson Sun, The Bloodstained Moon… This is the summoning spell for The Celestial Calamity itself. Everything matches, one to one. Hey, [REDACTED], why does King Asgore have this book at all? …What do you mean it’s ‘not important’?!”

Young Sans glared at the other person. “Alright, I’m gonna make you a deal. You want Papyrus to become a hero, right? Then let him grow up with a healthy foundation. No shortcuts. In exchange for giving Papyrus a normal childhood, I will become your secret weapon.”

That’s when the batteries went flat. Without power, the light on the magic circle died down and the holograms vanished. Darkness returned to the empty house.

Dust sat down on the ground, dumbfounded. “I… I was a secret weapon…? I thought I was a scientist…”

“What’s so bad about being a weapon?” The Phantom questioned. “It means you’re powerful! Deadly! Useful! Isn’t that why you’re alive today?”

“No… no there’s more to it. If I wasn’t a scientist, why would I have that broken machine under my old Snowdin house?”

An epiphany dawned upon him. The drawers back at his underground lab. Photos. Pictorial evidence. He knew he had left them behind. Since the location remained fresh in his memory, he hopped right over.

Dust then rushed over to his drawers. With a shining bone in hand, he opened them up and started rummaging. The first thing he dug up was an old badge. He quickly placed that aside since he couldn’t remember what it was awarded for.

Then, there was the photo album. While searching through them, he found pages and pages of people in lab coats. Scientists. Co-workers. Posing together with a youngster named Sans.

“I was always trying to return to those happier times,” Dust muttered. “But I couldn’t. One day… our workplace vanished. Everyone lost their jobs. Lost their purpose. We parted ways and never kept contact. Why? Nobody knows. It just sort of… happened.”

The deeper he dug into his past, the more questions arose.

At the end of the album, he found the group photo of the monsters who made it to The Surface. Frisk stood right in the middle, stoic as always.

That one picture was too much for Dust to bear. He slammed the album shut to avoid the pain.

It was then that a card fell out of the back flap. It’s a badly-scrawled drawing of three smiling people. Written on it were the words: ‘don’t forget’.

“Mom. Dad. And… a man wearing black clothes. Who is he? Why is he so important that he’s standing next to my parents?”

When he checked the lab photos again, he couldn’t find anyone that matched the drawing. But he did find something else. “Wait a minute… What’s this weird blur? Was it a defect in the processing? Or…? Ugh, there’s not enough light here. Better examine them back home.”

After packing the album, Dust turned his attention to the curtain. Pulling it aside, it revealed a steel mangled husk of a strange device. It’s hard to figure out what it used to be, and that could be part of the reason why he could never repair it.

Digging into the wreckage, he found a piece of a screen monitor.

“A viewing device?” Dust rubbed his chin. “I did think it was a computer of sorts. Or a processing machine. Maybe I was on the wrong tangent.”

“Sans?” The Phantom hovered over a gap, “I think there’s an extra chamber within the machine. Maybe we should try to pry it open.”

Pry it open? That’s something he hadn’t tried yet. He was so careful in preserving whatever integrity the casing had left, he didn’t dare to do so.

Using the bonelight as a lever, he tried to pry the metal open to access the hidden compartment. It was more difficult than Dust expected. If it once had a hinge, it may have been turned into a useless lump by all sorts of assorted damages.

Groaning, Dust said, “This is taking too much work. Stand back, I’m going to make a clean cut.”

Using his Karma, he carefully cut through the outer edges of the machine. Metallic dust trickled down to the floor as he worked.

After he finished, Dust used his telekinesis to move the whole piece aside. It revealed a strange inner mechanism, packed with wires and parts, connected to a central indent.

“…This hole… It’s big enough to fit a person.”

Inspecting the unusual indent, he noticed that its walls were engraved by layers and layers of magical scripts and spells. They lay dormant without any source of power.

The ghost commented in great curiosity: “My, oh my… that machine is chock-full of curses!”

Somehow, someway, The Book of Curses served as one of the foundational principles in its creation. Could that explain why Sans the Scientist couldn’t repair it?

In an effort to find answers, Dust found only more questions. To progress, he started to think that he needed to change his mindset.

“I see. I know what to do now. I shouldn’t have tried to fix it. No… I should have dismantled it. Starting from scratch, I’ll reverse engineer this device and build a better one.”