Note: This story came to me after seeing a Undertale sprite of Mabel and Dipper. The Mabel sprite looked a lot like Chara (probably cause Chara was used as a base) which made me come up with this brain child... Fair warning, this is not a happy story.

"Einey!" Bill shouted out as he gripped on to the twins, while their Grunkles watched in object horror as he was deciding which child to kill first with the changing of his eye (starting with an image of a pine tree).

They were captured as weirdmeggdon was about to fall and now it appeared to be the end for one of the children within Bill's giant hands.

"Miney!"

Several screams out to the children and the adults as the eye changed to an image of a shooting star trying to make Bill stop.

"Miney!"

All but one who stayed all too calm as the screams went on to stop or offers of exchanged lives when it changed back to the pine tree picture. One who had finally had enough of playing pretend and would play no longer.

"MOE!"

Bill tossed Dipper to the ground staring at Mabel with his eye now red with the black shooting star trained on her as he prepared to kill her...

But he had stopped when he saw she didn't respond to his freighting face or the idea she was now going to die, only looking down the bridge of her nose blankly, like she was hollow inside. Was she in shock of her on coming death?

Bill shook it off and said with his other hand in flame, "It's been fun messing with your minds and burning your world to the ground but now it's time to die Shooting Star!"

"... heh... heheh..."

A soft yet eerie chuckle emanated from Mabel's mouth but it sounded nothing like her voice causing all occupants in the room to stop and look at her a bit shocked. Something was wrong with her. They all knew it but didn't make a move until her expression changed.

She smiled... But not her usual friendly or overly excited grin that would warm everyone's hearts. No, it was sinister with her bangs obscuring her eyes from sight making it look as if she were the Cheshire cat only letting the world see that unsettling grin plastered across her face.

She then spoke in a chilling tone, "Oh Bill... You are quite clever and ever so sadistic, I'll give you that... But there's one thing you didn't count on in this little game of yours."

Mabel's head tilted up showing her soft brown eyes were gone. Now bright red and positively glowing with malice and hate had taken their place, making her already pale skin look ghostly.

She then declared in almost a whisper, with the grin still in place, "That you were the only player on the board~!"

A flash of red light slid across Bill's arm making it fall off and Bill hiss out in pain while Mabel gently floated down to the ground as if the 40 foot drop it was nothing but a step forward.

Her whole demeanor had shifted in an instant, she stood with her feet a bit apart, arms at her sides facing towards Bill as he tried to heal, and back towards her family. But what was most concerning of all was the very sharp and equally large kitchen knife she had in hand that leaked with the blue goo that came from Bill's dismembered arm. Even more so she carried it like she knew what she was doing. As if she had done this a hundred times over.

Dipper looked at his sister in concern and a slight fear and said, "M-Mabel? Wha-"

" 'Mabel'... Hehe... You still think-! Hahahaha! You think she's still here! HAHAHAHAHAHAHA! That's quite delicious that you're so ignorant!"

She turned her head towards Dipper with that sadistic smile still on her face and said, "Mabel's been sleeping for a long time and she won't be waking up anytime soon~! Hehehehe!"

Dipper yelled out in shock, "WHAT?! WHAT DID YOU DO TO MY SISTER?! WHERE IS SHE?!"

'Mabel' gave another laugh and said, "Now, now, I didn't do a thing, your lovely little twin gave me this body and SOUL years ago. So kind and sweet... And all too naïve, hehehehe... You see she's right here... But she's not coming back dear brother... She left it all to me..."

Dipper stepped back and said, "N-No... It can't be true! Mabel would never..."

'Mabel' took her hand out and now in front of her stood a cherry red heart pulsing with power wrapped with sickly black vines burrowing in and out of it dripping with black sludge from the entry holes.

Ford immediately knew what the heart was and was now looking at his great niece in horror and fear. He whispered, "That... That's her... "

"You mean my lovely given SOUL ? Yes, isn't it wonderful, it's been in my possession for the last 9 years. Still as lovely as the day she gave it to me." 'Mabel' declared shoving the sick looking SOUL back into her chest.

"9... 9 years... You... You impersonated my sister... FOR 9 YEARS?!" Dipper shouted tears slipping down his cheeks with righteous anger.

'Mabel' stepped closer to Dipper and stated as she walked, "You're quite slow to this aren't you? Let me ask you something Dipper. Did you see the changes in your sister? Did you or did you not? How she suddenly gained rosy cheeks over night, or how she could now fight with her bare fist... Hell, when that unicorn stated that there was darkness in her heart... When did you see those things? Please, enlighten me."

That had hit Dipper hard... He, who was suppose to know his sister better than anyone else, didn't see any changes... Not one...

How...

He felt to his knees.

How could he not have seen anything?!

'Mabel' was now a step away from him.

She twirled her knife in her hands and said, "You saw nothing! You didn't see a thing! How pathetic! You call yourself a good brother when you're nothing a but a worthless whelp who couldn't see what his own 'sister' had become! You didn't do a thing to find what had changed in her and now you see the results of your neglect!"

'Mabel' held the knife high in the air and said, "She made her own path when she fell down Ebbot and entered the realm of the monster kingdom! She gave me her very body and SOUL when I asked her for it! And what did I do with it?"

She let out a deafing cackle as she directed the knife at the still crying Dipper. " I KILLED THEM ALL! EVERY SINGLE MONSTER THAT WAS TRAPPED DOWN THERE! THEY'RE ALL DEAD! NO SURVIOVORS! NOT EVEN CHILDREN WERE SPARED FROM MY BLADE! NO MERCY! COMEPLETE GENOCIDE! And the best part... I made her watch every single one to let her know what exactly she just did."

Stan, who before hand had stayed quite, was now very angry and trying to escape his cage to get at the monster in his great niece's body. " YOU SICK BASTARD! YOU MADE HER WATCH YOU KILL THEM?! HOW COULD YOU?! HOW FUCKING COULD YOU!?"

She placed the blade at her lips and said, "Like this."

And before anyone knew what was happening the knife had made a red mark in the air and fired... Right at the prison tapestries of the Cipher Wheel...

All of them felt to the floor, cut in half, and oozing out blood and screams of pain and agony. Finally there was silence once more other than the drip of blood coming from the other half that still hanged up.

Bill who was still trying to recover his arm was also shocked at what she had just did.

Mercilessly butchering the ones she called friends...

This human... No, whatever this thing was just a cruel as he was... Possibly even crueler if this was only the start.

She laughed in delight and said, "Ahahaha! What a wonderful feeling! Can't believe I ever stopped doing this!"

She held the knife up again turned to the cage. Soon the bars were cut open and she was moving towards the twin brothers with her white sclera turning pitch black.

The slaughter that followed truly showed what monster they were truly dealing with.

This... Creature wanted nothing but to kill and not to do it fast. No, it drawled it out and made it as painful as possible, both mentally and physically. It took it's time slowly killing the two, even as they fought back with all they had, they were simply no match for it.

Now it stood drenched in fresh blood, smiling like it was Christmas day and it got just what it wanted, it's eyes a glow behind the pitch black sclera, and the knife in hand as it sadistically licked the blood off the knife.

Dipper was deathly pale and more scared than he had ever been in his life. He had just watched this monster wearing his sister's skin brutally murder his great uncles, which had made him vomit until he was dry heaving in sheer agony.

When he looked up the creature was leaving the cage and heading this way. This monster had it's eyes on him for it's next victim.

Bill, who in his time had seen many death at his hands and the hands of his friends, enemies, frienemes, and so on, hadn't seen a death that... Gruesome... And now as it approached the boy, he had a feeling he was going to witness another one.

The Creature was now in front of Dipper, holding him up by his throat in one hand while the knife was held in the other.

It chuckled and said, "Any last words my dearest brother before you die?"

Dipper who was gasping between tears of fear, sadness, and pain, whispered out, "Why...? Why do this?!"

That for the first time made it's madding grin vanish. It then spoke softly, "This world is nothing but wretched, vile, vulgar, and much more wrong doings. It is a poison corrupting even the most innocent of things... I'm simply freeing those I kill from this vile existence... And once they all have been freed, I shall erase this world and nothing will remain..."

It looked up at him and said with tears drenching it's face with a soft smile, "I'm doing this because I love you and I don't want you to suffer this world any longer... I smile because I am freeing you!"

It then shoved the knife into Dipper's throat and slit though his esophagus while looked at it wide eyed in shock.

It brought him down and kissed his forehead and said soft and lovingly, "Now be free brother... And know this world will be erased by my hand."

It set him down gently and watched as Dipper slowly choked to death on his own blood looking up at the monster who had 'freed him'.

It now had one last target within the room who for some reason still hadn't healed.

He yelled, "WHAT THE HELL'S GOING ON?! MY ARM ISN'T GROWING BACK!"

"That's because this, dear Bill, is no normal knife."

All of a sudden the world turned black and white for Bill.

A text box had appeared in front of him along with his very disfigured soul.

*The Real Knife- Weapon AT-99

"Here we are."

The Creature held up it's hair and with a line of red, cut off the long locks leaving a medium length bob cut. It then slipped off the blood soaked sweater and not had a striped one equipped with a glowing heart locket over the top of it. Another box popped up for Bill.

*The Locket- Armor DF-99

"You can feel it beating."

This creature no longer bore any resemblance to the girl he had first encountered when he was summoned back to Gravity Falls.

It was all to obvious that this creature intended on ending everything. His games, his conquest, his worlds... Even his very life now hanged in the balance.

And now, he had to defend it.

He looked at it and said, "Before we start, I've got one question for you... One from the very moment, you showed your true self... If you're not Shooting Star, then who are you?"

The creature gave a heartily laugh and said, "It is true, I seemed to forgotten my manners..."

Bill watched as black ooze leaked from it's mouth and eyes as it said, " Greetings. I am Chara. "

End

(Yep... That happened... Please don't kill me for writing this...)

This is also on AO3