Hey everyone, i'm writing this One shot due to a request from a friend of mine. It's set a couple days before the play in the episode Sock opera. That's pretty much all you need to know, so enjoy! Also i'm incredibly sorry but there's like a 90% chance Bill will be completely out of character. So, apologies.

Mabel Pines sits at a table in the attic of her Great uncle- Or, as her and her twin brother fondly called him- Grunkle stan's house and locally-famous tourist trap, The Mystery Shack. It had become a sort of home-away-from-home for her, as had the entire town of Gravity falls, oregon. She looks around the room, a soft smile crossing her face, until her eyes stop, focussing on her twin brother, Dipper. He has been trying to figure out how to unlock a laptop he had obtained after a recent adventure, and it was beginning to get creepy how much he focussed on it.

"C'mon, mabel," He'd always say, "I'm trying to figure out the secrets of this town. Something's up, i know it! I just want to figure it out…" So while he obsessed over that, she focussed on her own goals. Namely, the boy she was currently fawning over, by the name of Gabe. She'd usually be able to get her brother to help her set up the massive puppet show she was using to try to win Gabe's heart, but there were some days- like this one- where she just couldn't make him put down that computer.

She looks out the window, and watches the sun slowly descend over the treetops, allowing a sigh to exit her lips. "Hey bro-bro, i think i'm gonna go to bed... Gotta be prepared for a long day of making puppets tomorrow, y'know!" She lets out a half-hearted laugh as she says this. Dipper looked up from the laptop, a concerned expression on his face. "Um… Alright, sis… It's still pretty early, are you sure you want to go to bed?"

Mabel just nods quickly, forcing a smile. "Yeah, i'm fine bro. Just feelin' a little tired is all." She gets up, and walks over to her bed. She lays down on top of it, and goes to sleep almost instantly. Dipper stares at her for a few moments before getting up, and walking over to her, putting her blankets over her. She smiles a little bit in her sleep, and dipper returns to his bed, getting back to work.

-Meanwhile-

Bill cipher was, as he usually does, keeping an eye on everyone and everything in the world simultaneously. Laughing at people's misfortunes, visiting people in their dreams, making deals with the gullible and desperate, the usual. Despite things going as normally as they were, he couldn't help but feel… troubled. In the sleepy town of gravity falls, oregon, a pair of siblings were getting far too close to the answers to some pretty major questions concerning several secrets, most of which involved himself. He didn't want that to happen. So, he formulated a plan.

Shooting star. Sweet, innocent little Shooting star. Nobody would suspect her of anything, least of all her dear brother. She's the perfect tool. Bill cast his All-seeing-eye upon the Mystery shack, scrutinizing it, waiting for the perfect moment to put his plan into action.

Finally, an opportunity opened.

"Yeah, i'm fine bro. Just feelin' a little tired is all." Bingo. As the female twin drifted off to sleep, Bill took the opportunity, and appeared to her.

Mabel lays in her bed, an odd feeling overtaking her mind. It's like she's asleep, yet… awake. She blinks a few times, and sits up, realizing two things that scared her out of her wits. One, Dipper was gone without a trace, and two, she seems to have gone colorblind. She looks around, terrified. "D-Dipper? Dipper, i think i've gone colorblind!" She walks to the bedroom door and tries to open it. Locked, from the outside it seems.

She bangs on the door with her fists, hoping to get the attention of someone in the hall. They'd let her out, and Dipper would find something in that book of his to make everything less gray. She keeps banging on the door, quickly losing track of time.

She stops, when she hears an odd noise behind her. An indescribable sound, one that she has heard once before. She turns around, scared, and watches as a triangular hole in our universe opens, allowing a demonic entity she had hoped not to see ever again directly into her mind.

"Bill…." She gasps, eyes going wide as she realizes exactly what this could mean. Why was he in her mind? Had someone sent him? Was it Gideon? Countless questions fly through her mind as the being known as Bill Cipher phases into her mind.

"Well, well, well, if it isn't my favorite little nuisance! How're you, shooting star?"

"I was doing fine 'till you showed up!"

"Aww, that's no way to treat an old pal! You should know that. Or… Do you? Jeez, here i was thinking you were a good little girl! Guess i was wrong, eh?"

Mabel glares at the Dream demon. "What do you want, Bill? Did Gideon send you? Are you here to make me go bald and ugly or something?"

Bill laughs, and rolls his eye. "Kid, calm down! You can't judge me as a whole based off of one job i did. I'm not like that, really!" He gives her his best attempt at a sincere look, and her glare falters a bit.

"Well… I mean, i… i guess you're right…" She looks down, thinking. Is he a bad person? Surely, he is, after all, he took the job in the first place! No good person would take that job! Right?

Bill, seemly reading her mind, vanishes and re-appears right next to her, putting an arm around her shoulder. "Aww, c'mon kid! You can trust me! I've done all kinds of things, good things, bad things, it's a mixed bag! You just happened to see me doing one of the bad things. But y'know what? I'll show you that i can do something good. Let's just cut to the chase, I think there's something you want that i could help you with…"

Mabel's eyes widen as she looks at the demon. "You'll get Dipper to spend time with me instead of trying to solve those stupid mysteries?!"

Bill stares at her. "...Beg your pardon?" He quickly shakes his 'head'. "Uh, i mean, yeah! I'll… I'll help you with, eh, with Pine tree. Though i kinda thought you'd want that puppet guy to… Nevermind!" Bill gasps as Mabel tackles him, wrapping her arms around his body. "Thank you! Thank you so much! I was wrong, you're not a bad person, i'm sorry i even thought that!" For half a second, Bill considers pushing her off. But, realizing that would possibly ruin what he's trying to do, he just lets her stay.

"Uh… Thanks, kid… Gee, you… Really like to see the best in people, eh? That can cause problems, y'know." Mabel looks at him, a confused expression on her face. "What do you mean?" Bill just stares at her. "Are… Are you serious? Kid, trust isn't just something you can… Know what? Nevermind. Trust whoever you want, don't let me stop you."

Mabel watches him skeptically for a few moments, before shrugging, simply accepting what Bill was saying. Bill scratches the back of his head, unsure of exactly what to do. "So… Um… Ah!" Bill remembers the plan he had, and backs up slightly. "So, terms of the deal have been set. That's good. All we need to do now is seal it. Just shake my-" Bill isn't allowed to finish his sentence, because Mabel leaps at him, hugging him a second time.

"I prefer hugs over handshakes." The little girl smiles a bit, unaware of the fact that Bill is beginning to get Annoyed. "Yes, okay, that's fine, but i kinda need you to shake my hand. That's… That's how i work. Do you understand that? If i don't shake your hand, the deal won't be official."

Mabel looks at him, confused. "Who cares if it's official? You're in charge of yourself, right? Don't you decide what is and isn't official?" Bill's eye twitches involuntarily. "...No. No, kid, that… That's not how it works. That's not how deals with me work."

"And why not?"

"It's just how i work."

"And why do you work like that?"

"Because i do."

"So?"

Bill shuts his eye, exasperated. "For the love of… Hey, shooting star, could you excuse me for a moment?" Bill begins to turn around, but Mabel stops him. "I'll let you do whatever it is you need to, but first, i want you to promise something." Bill glares at her from the corner of his eye. "Aaaaand, what is that?" She smiles a bit. "Just call me Mabel. No need to call me 'shooting star', we're friends, after all."

Bill considers his options. On the one hand, he could just suck it up and do what she wants in the hopes she'll be a good puppet for him, or he could call it quits, tell her he's not her friend, and make an attempt to persuade the more strong-willed members of the Pines family. After a few seconds of thinking, Bill sighs. Stan wouldn't be incredibly helpful, and pine tree would never agree to make a deal with a demon, especially not a demon he has encountered before…

"Fine. You drive a hard bargain, Shoot- I mean, Mabel." Bill shakes his head. He's so used to calling people by their symbols. Clearly, he's going to have to strain himself to work with the girl. Bill floats away from her, considering what to do next. He looks back at her. She's sitting on the ground, holding her hands up like puppets, making them talk to each other. Bill watches her curiously for a moment, before floating back to her. "Uh, Mabel, what are you doing…?"

She looks up at him. "Planning scenes for my puppet show. You wanna help?" Bill narrows his eye slightly. "Why would i help with that? That's not what i'm here for, kid." Mabel stares at him with the most pleading puppy-dog eyes she can manage. "Pleeeeeease, Bill?"

"No."

"Please?"

"No!"

"Fine! Deal's off, then!" Mabel grabs her arm between her index finger and her thumb. Bill realizes she's going to try to wake herself up by pinching her own arm, and he steps in. He grabs her wrist. "Whoa, kid, let's not be so hasty! I've changed my mind. I'll… Help with the puppet show, or… Whatever."

Mabel squeals, and begins spreading her arms. Bill, realizing what's about to happen, pulls his cane out of thin air. When mabel leaps at him to hug him, he sticks his cane out, using it to keep her at bay. "Just… No hugging." Mabel makes a pouty face, and begins reaching towards her arm again. Bill groans. "You're going to just hold that over my head, aren't you?" He gets rid of his cane, and Mabel smiles, wrapping him in a third hug. "Yep!"

Bill looks at her out of the corner of his eye. "Fantastic." Mabel doesn't notice the sarcasm dripping from his voice.

-Five minutes later-

"Okay, first big problem. I've got most of the story in my head, but i haven't got any ideas for songs. I want a bunch of them, all completely original, but i don't know how i'm supposed to make them in the short time i've got." Bill gives her a knowing look. "I think i know a guy…"

-Two hours later-

"Hmm… That's a good idea, but it could be a lot better, story-wise. I mean, If he dies in the war, the audience will leave sad. We don't want them sad. We want them to be happy!" Bill considers this for a moment. "Well, i guess you've got a point. I'd prefer the death though." Mabel laughs. "Why am i not surprised?"

-One hour later-

"Then at the wedding, You could appear!" Bill looks at her. "...Me? Why me?" She smiles. "Because you've been a big part in helping me create this story, silly! Not to mention, you really love putting your face on everything you possibly can."

"And what makes you think that?"

"I've noticed things that look like you all over town! I thought it was just weird at first, but now i know it was just your ego. You wanted people to put you everywhere!" Mabel giggles. Bill lets out a quiet chuckle as well. "Okay, you've got me. Though, that's actually kinda part of how i watch over everything everyone does."

"What was that?"

"Nothing."

-Four hours later-

Mabel bounces up and down on her feet, excitedly. After completing the creation process of the puppet show, she managed to get Bill to show her what it would be like if everything went exactly to plan. She sits cross-legged on the floor, Bill floating next to her, focussing on keeping the show going for her. She giggles, and looks up at the floating triangle demon. "Thanks, Bill. For everything." Bill glances at her. "Eh… Don't sweat it, kid. Now keep quiet, need to focus." Bill turns his attention back to the projection of the puppet show.

-One hour later-

Mabel jumps up, clapping excitedly. "Bill, that was amazing! I don't even know what to say!" The demon looks at her, glad he doesn't have a mouth, because if he did, he'd be smiling. "Yeah, The fireworks at the end there were actually my own little last-minute addition. Don't worry about going out and getting them, i'll hook you up." Mabel smiles, giving him a fourth hug. "Thank you so much, Bill. For everything." She seems to consider something for a moment, and shrugs. Bill looks at her, about to ask what she was thinking about, when she leans in and kisses him about where his cheek probably is. She lets go of him, and he floats back slightly. "Now, guess i've gotta shake your hand or something to seal the deal, right?" She holds out her hand.

Bill quickly grabs it, a blue flame engulfing their arms. "Now, Bill! Take her body! Possess her, and use her to get Pine tree's journal!"

"..."

"...Now!"

"...Okay, now!"

Bill lets go of Mabel's hand. "Pleasure doing business with ya, Mabel." He begins to float upwards, but before he can disappear, Mabel grabs his ankle.

"Wait, Bill!"

"...Yeah, kid?"

"Promise me you'll come back sometime…?" Bill stares at her. "Here's your second chance to make her your puppet Bill, don't mess this up!"

"...Promise. No handshake this time, you've got my word." And with that, he vanishes.

Mabel wakes up in her bed, well-rested and ready for the next day. She glances at her hand, and notices some writing on her arm.

"Check the table -B.C."

She looks at the table, like the writing told her to do, and she gasps. Sitting atop it is a three-ring binder that she knows wasn't there the previous night. Inside it is the script, completely written, and several lyrics sheets for songs. All the songs she had seen in Bill's projection of the play. She looks up, tears of joy in her eyes. "Thank you so much, Bill!" She whispers.

-Meanwhile-

Bill sat in the mindscape, as always, watching over everything. Though, he wasn't paying too much attention. He was busy thinking about the previous night. "Alright… So… Recap. I went into Mabel's mind, and got completely sidetracked. I did not get access to her body, and i am no closer to destroying the journal." Bill groans, before an idea comes to mind. An idea he had before, but dismissed. He turned his attention to the male Pines twin. He laughs quietly. "Alright, so, plan B. Watch out Pine tree, here i come…"

There ya go! My Gravity falls one-shot. Shoutout to my friend who requested this, you know who you are! I honestly had a lot of fun writing this, so… Yeah. Hope you all enjoy reading it as much as i did making it!