Chasm (Sans)

*“Sans I’m sorry. . .I’m so- so sorry”*

                                          -Alphys

**Chasm** is one of the many terrors hidden inside the **Prosthetic-verse**. He hails from the alternate timeline that has come to be known as **PresentTale**. A malevolent and grotesque being that slithers through the many worlds that the multiverse contains. Best to avoid at all cost and simply leave nothing to chance.

***Backstory:***

Once an ordinary Sans, but now a target for Geno’s grandiose plan of destroying the main Undertale timeline. Sans was deemed suitable to make this dream come into fruition. Geno had been upfront and simply asked nicely for Sans to join him. To which, Sans rejected the offer seeing no sense in the destruction of his timeline or any others’. Not interested in taking no for an answer Geno would wipe Sans’ mind of their encounter.

This would begin a long strenuous streak of both physical and mental torture that would continue to end with Sans refusing to Geno’s plan. This progression would cause Geno to become furious and violent, lashing out his anger at Sans by forcing him to relive the genocides Geno experienced, hundreds upon thousands of times. Sans had hit rock bottom, he had tried being peaceful and even attempting to fight back against Geno’s tyranny. Practically one step away from his breaking point, Sans contemplated joining Geno but simply couldn’t bargain away the lives of those in his timeline or the lives in any other timeline. He had to protect them, he was the only one who could protect them. All of them. Every. Single. Last. One.

*‘Slippery. . .’*

Alphys could hear it even over the blaring sirens of the underground. The ear piercing screams of the innocent rattled the reptilian to her core as everyone she knew was surely gone. What had she done? This was all her fault if she had just- maybe she could’ve- what does it matter anymore? She had barricaded herself in a panic room within her lab. It had felt like days even though in reality it had been just a couple of hours since the creature had emerged deep from within the true lab. Long since, dry tears stuck to her yellow face as bubbly snot dripped down to her lips. She pondered if Undyne was still out there, even if the chances were slim, she’d hold the tiniest bit of hope in her heart that Undyne was okay, alive. Alphys would soon start to chew on her nails. The crunch and snapping kept her mind at ease as she didn’t even notice when there was nothing left of them. Tearing at the skin of her finger tips as she’d bit away the scaly flesh, causing blood to ooze out. How long would she last here? The metal paneling was cold to the touch and the low buzzing hum of lights was nauseating. Though the worst of her situation was all contained in her own mind. The pessimistic thoughts, the overthinking, and the idea of what could be happening on the outside. It created a cesspool of hysteria which she was sure to fall to. If whatever creature that wandered behind the reinforced walls didn’t get to her first. The sudden sound of knocking would jolt Alphys out of her own induced fear and anxiety. She turned and looked towards the heavily reinforced door which sat behind her.

“Uh-hhhh wh-who is it?” She stuttered, unsure what to make of this random event, though regardless her voice quivered past her lips.“It's me Alphy! I’ve lost touch with my troupe but it’s really bad out here – whatever that thing it's torn through the underground! Let me inside so we can hatch out a plan!” Undyne spoke with urgency. Her heart would flutter and tears of happiness would drip down her rosy red cheeks at a familiar voice.

Alphys, relieved for the sense of comfort, the sense of familiarity in this crisis, rushed towards the door to quickly pull her lover inside but stopped. Her chewed fingers just centimeters away from the keypad, which resided at the center of the door.

“Come on! What are you waiting for?” Undyne barked, an unease in her voice.

Alphys felt herself sweat before she took a few steps back. Quickly, she began noticing something was wrong about this. An immense pressure on her chest telling her not to open it, fear? Worry? The dread that this wasn’t Undyne..? She began to review her knowledge on the other entities in the true lab.

“What’s my favorite anime…?” She questioned the uncertainty in her voice so apparent, you could feel the shaking in the air. There was an abrupt silence, an uncomfortable quiet, before there was finally a response to Alphys’ suspense..

“Mew Mew: Kissy Cutie- listen, Alphy can you just please open the door?” Undyne yelled, shattering the silence.

“Wh-why did you join the royal guard…” Alphys shot out another question still not completely sold on the idea that this could truly be Undyne. The fearful paranoia eating at her.

“THIS IS POINTLESS JUST LET ME IN ALPHYS!?” Undyne growled, a sparking annoyance in her tone.

“ANSWER THE QUESTION!!!!!!” Alphys yelled in fear, her voice rattling as she would feel herself pull further away from the keypad on the sealed doors.

Once again there was a painful silence that only furthered Alphys’s suspicions, but unlike before there was the sound of running footsteps as another voice rang through the halls.

“UNDYNE!?” the voice yelled

“PAPYRUS IS THAT YOU?” Undyne said in surprise.

“THAT THINGS ON ITS WAY!!!” Papyrus raved frantically, letting out a heaving breath of fear.

A blood curdling screech would pierce Alphys’s ears as her paranoia was swiftly shoved in the back of her mind. She’d quickly rush to open the door, slamming in the code for the keypad and readied herself to pull her friends inside. Sadly what she was expecting was far from the reality, as there was no Undyne nor Papyrus. Just a white mangled pustule of fleshy mass repeatedly warped through the faces of all those it assimilated into itself. Alphys would feel her heart sink deeper into her chest as she tried to slam the door shut. Tears formed in the corner of her eyes, as the disgusting pus from the giant godforsaken fresh pile would spill onto the ground as the creature banged against the door. Forcing itself through the tiniest opening that it was offered. Regardless of Alphys’ desperate attempts to close the metallic doors shut, the obstacle was hardly enough to stop it. As the creature created several new appendages from its own balled up flesh to completely rip the reinforced mechanical door off its hinges. Slamming them to the side with a sharp clang as Alphys heaved, uncontrollably crying as she backed away, stumbling herself into a corner huddling around her knees. The grotesque abomination quickly approached to pull her into the same fate as the others, when suddenly Alphys, out of fear, blurted out.

“Sans I’m so sorry- this is all my fault- please-“ She squealed as the ginormous bundle of flesh moved forward, closer to the reptile as a long shadow loomed over her. The creature's size began to condense and shrink, twisting and compressing before it resembled an uncanny recreation of Sans. It moved its hand towards Alphys’s ear, quickly shifting its form as its palm held the side of her face.

“Aaaaaaaaalphyssssss itsssssssss your fault- help ussssssssssss Aaaaaaaaalphysssssssssss” The head of Undyne said in a heavily distorted and murky voice.

Alphys flinched and continued to sob, unable to even stop herself as this creature that was once Sans crept closer. The swirling vortex of darkness that was its face forcefully sucking her in before doing the same to itself. The process resembled a snake eating its own tail before just like that. They were gone. The only thing left, telling the events before, being an eerily empty underground where not a single living being could be found.

**Personality:**

Before meeting Geno, Chasm was just your average Classic Sans with the same old routine and gags. Scamming kids with fried snow, cracking bad jokes, and spending all of his time at Grillbys, but due to the physical and mental torture done to him by Geno. He’s been reduced to nothing but a shattered mind. Where a violent and sociopathic personality had uprooted itself in Chasm's desperation and helplessness at the predicament he faced. Now possessing an utter belief in the fact that he is the only one that can protect his friends, and that he knows what's best for everyone, even to the point of physically and mentally abusing those he loves. He’ll gaslight and manipulate to get his way and isn’t above killing those that stand in front of him from freeing his timeline of Geno. After exposing himself to determination and working his way to the amalgamations locked in the true lab. Sans himself became one as well. Sans’s mind became very distorted, jolting his sociopathic and controlling tendencies to the absolute max. Making him a truly malicious and violent being, that simply runs off the last clear objective that was left in his former self’s mind before assimilation with the amalgamates.

**Quirks and Details:**

* When not mimicking voices Chasm only seems to repeat the word “Slippery” to varying degrees, tones and pitches.
* Chasm's face is a direct gateway into a small widely separated portion of the save screen.
* Chasm can sometimes be observed doing the daily routine of some random being he’s absorbed.
* Chasm has a total of twelve fingers on his hand due to one extra thumb being on the end of both of his hands.
* Chasm suffers from predicaments, which due to his amalgamated body and just how much biomass he’s absorbed he simply doesn’t have enough DT to keep it altogether causing him to lose all shape and become a puddle of white flesh.
* Chasm and Alphys on occasions engage in tabletop games such as Warhammer 40k and Dungeons & Dragons.

**Relationships:**

**Geno!Sans:** Chasm despises Geno, though the two haven’t met since the incident and have for the most part stayed away from one another.

**Mis-Hap:** The two have encountered each other on many occasions, usually ending up in a fight in which Mishap runs away utterly terrified. Mishap hates Chasm for the simple speculation and paranoia that Chasm could potentially be the Geno to his Error. Though he has no evidence to back the theory up nor prove its validity.

**PresentTale Alphys:** Reduced to an extremely depressed caretaker of Chasm. Being psychologically and physically abused at every turn and frequently gaslit and manipulated by the use of her lover's voice. She believes this is all her fault though she has no idea about the events involving Geno and Chasm.

**Core Frisk:** Believes that Chasm is one of the biggest threats to the multiverse and has no hope of salvation. Believing that the right thing to do would be to put the creature out of its misery.

**Powers & Abilities:**

Assimilation

When Chasm absorbs a being he receives their memories, fighting experience and abilities.

Razor Swarm

A swarm of amalgamated butterflies graft off of his body and are extremely deadly being akin to the behavior of locust. Chasm can also transform his entire body into these butterflies for evasion or even a quick escape.

Ribbon Blasters

Being heavily affected by the process of amalgamation these blasters have lost the ability to shoot beams or lasers but instead shoot out a mass of flattened organs (akin to that of the Ribbon Worm hence their name sake) before then pulling whatever gets caught back into their jaws.

Alphys’s Handiwork

Alphys has created several things to help Chasm on his daily hunts all in an attempt to pay back what she thinks was her fault. These innovations are as listed:

* Skeletal Frame: a metal frame in the obligatory shape of a skeleton to help Chasm with ascertaining his Sans esque shape. It’s capable of a few defense measures such as being enveloped in electricity or causing serrated spikes to erupt from Chasms body.
* Parasitic Life Form: A parasite that takes the form of Chasms scarf and is capable of lunging at enemies or shooting out photons of bioluminescent energy from its teeth.

Amalgamated Biology

He is able to shapeshift any area of his party to form weapons or even extra limbs. He can mimic voices and even take their form though they’ll appear heavily uncanny and grotesque.

**Objective:**

To protect everyone which was the last thing that Sans had so heavily focused on before becoming Chasm. Causing him to absorb everything in a twisted way to secure its eternal safety by becoming one with it.

**Sightings/Rumors:**