A/N: Be warned that this is my first Gravity Falls fic and I absolutely have not read any fics of this fandom yet. This pretty much means whatever popular headcanons most fans agree on, they probably won't apply here.

I'm also still not entirely certain where this fic will lead but it'll be much appreciated if you tell me what you think!

He's asleep. He knows that very well. Whether that's a factor of the procedure or not, the case that he's positively aware that he's in a dream feels all too surreal for him. It's not even his dream to begin with. It's Stan's, and he's not entirely sure what's supposed to be happening here.

The young man stands in the middle of a plain green meadow, barely a touch of wind could be detected. The sky is flushed pink and twinkled gold over the lush field. Even if he squints, he could barely make out any form or shape from afar. Where's Stan? This is his dream after all. He hesitates, his arms folding over his chest. He has been assured that this experiment would be completely harmless and since that reassurance had come from Ford himself, then he knows that there's nothing to be afraid of. He could wander around and come across some kind of enormous supernatural being but in the end, he'll just wake up and disregard the prior events.

"Okay, let's do this then." He convinces himself with a deep intake of breath.

Finally, he takes a few steps forward—his bright cerulean eyes taking a gander of his surroundings in hopes of catching sight of anything other than grass.

He continues to walk with no particular destination in mind.

Before long, he feels himself growing restless. Knowing Stan, he had expected the old man's dreams would be a lot more obscene and crummy than this one. This dream has more of a Ford touch. Slowly but surely, he could already feel the strength draining from his knees from treading on for far too long. He didn't even know that's possible when you're in a castle in the air.

Goddammit, if he had known this is how old people dream, he wouldn't have volunteered to do this in the first place.

At long last, a familiar bark of laughter captures his attention and the young blond whips his head up in an attempt to look for the source. He knows Stan's laugh anywhere. It's rambunctious but hoarse at the same time, a sound he's gotten all too accustomed to as much as he doesn't want to. Taking a few more steps further, he finally catches a glimpse of the Mystery Shack from afar.

Fuck yes.

With a grin curling his lips, he hastily picks up his pace. He could see the shack growing nearer the longer he sprints, Stan's laughter getting even louder. For the first time in his life, he's not even annoyed by the mere sound of it. The old man's laughter is soon joined in by a delighted one and it doesn't take him another second to recognize it as Mabel's. Now knowing that she's also in the dream—even if it's not really her—the young man grins wider.

Until an object instantly puffs up in front of him in a thick blast of grey smoke.

"BOO!"

A yellow traingular object comes up in front of him, its large one eye beaming down at him. He lets out a fleeting scream, his feet skidding to a halt before losing his balance and falling down on his rear. He gawks up at the floating shape in front of him, completely bewildered. It appears to be sporting a black tie over what he could assume would be its chest and a thin top hat floating over the tip of its shape. The pattern of a pyramid fades down to its lower half and its eye still continues to take him in as if it could see every negative quality he has and even likes him more for it.

It bears a strong resemblance to the Eye of Providence and for a second, he believes that it is the all-seeing eye of God.

Until it starts cackling at his misfortune.

"Oh boy, you should've seen the look on your face, kid!" Its voice sounds naturally mocking, layered with faint echoes. He doesn't like it already. "Sorry," It snickers in an impudent manner. "I didn't know the word 'BOO' still has its charm." A thin black cane materializes out of thin air and the yellow creature twirls it around with one of its dark thin arms.

"Oh god…" The blond murmurs in utter bewilderment.

"You can just call me your new lord and master for all of eternity!" The creature corrects him all too enthusiastically as it draws nearer to his face. "Or Bill, if you want to be casual about it."

He struggles to find his voice. What the hell does Stan dream about? Is he part of some fucked-up cult?

"…w-what are you?" He finally manages to croak out, backing away a bit in an attempt to maintain some safe distance between them.

Its large single eye blinks at him. "Weren't you listening? I just told you! Wow, you deafinitely need to clean your ears, kid." It cackles again, louder this time as it brings up its hand to wipe a nonexistent tear from its eye. "Get it? DEAF-INITELY! I'm a riot." It continues to laugh at its own joke—but then the young man realizes that since its name is Bill, then it's mostly likely that the creature is a guy.

Bill lowers down to meet his eyes and the blond doesn't know why but he could feel the creature smiling at him.

"So what brings you here?" Bill asks, interested. "You're a new face."

"I-I… I… I… I… um…"

"Yeah, yeah, I know. I've got one eye. Don't have to be rude about it." Bill narrows his eye at him before drawing away, crossing his arms over his head—isn't the entirety of his body technically his head though? "So who are you? And what are you doing here in Stan's dream, hmm? Is there some kind of fantasy the old man has that I yet to have the misfortune of witnessing?"

"What…? N-No!" Finally, the blond comes back up to his feet—his heart pounding a mile a minute. "I'm not part of his dream. I'm just in his dream… s-so, can you please get out of my way so I can find him? We're supposed to meet up and—"

"Whoa, whoa, hold your horses." Bill brings up his hands, his cane floating just right beside him. "Are you telling me that you've just somehow managed to get into his dream? That you, by some means, actually exist and are asleep right now?"

The blond pauses, but then slowly nods his head. "Um, yeah…"

"Hm," Bill narrows its eye again. "you must be one smart kid then."

"Not really…"

"No, you are!" The triangular creature draws closer to him again but this time, he manages to politely consider the young male's preference of the stretch of distance between them. "Trust me, I've seen a lot of people try to conjure up machines and whatnot just to get people to share dreams, you know. All of them have been futile. But you…! You must be one hell of a genius to be able to accomplish something as difficult as this!"

Awkwardly, the blond rubs the back of his neck. "I… technically didn't invent the machine. It was Ford—erm, Stan's brother."

"Ford, huh?" Bill folds his arms. "Then why are you here instead of him?"

"I volunteered." The other male shrugs. "He said that he's still not 100% sure it will work and… well, Stan looked sorta desperate to figure out what's been causing his nightmares lately so I've decided to volunteer to check if the machine works or not. So… yeah, I'm not that much of a genius as you think I am."

Bill is silent for a second or two, as though still drinking in the new information. But then he tips his hat to his companion and he smiles—or at least his eye tries to show that he is. "That sure doesn't change the fact that it's pretty daring of you to take this kind of risk. You do know that there were times wherein Ford's inventions didn't work out the way he wanted them to, right? You could have possibly gotten yourself killed. Or worse, you could have wiped yourself from existence if things didn't go well."

What? He didn't know that. Shit, does that mean he could die by the end of this?

"This isn't the first time Ford had tried this kind of invention." Bill goes on, twirling his cane again all too casually. "And let me just tell you, the guy who volunteered… well, let's just say he didn't get his money's worth when he realized that he was forever stuck in the other person's mind. Completely forgotten by everyone. But I'm sure Ford has told you all about that which is why that makes you one hell of a brave kid." He reaches over to give his only companion a soft friendly punch on the arm.

But the blond feels his pulse leap at the thought of the same thing happening to him.

No, Ford wouldn't let that happen.

Would he?

"You okay there, kid? You look a little green."

"Am I going to die?" The young man blurts out, panic slowly rising in his chest. "I mean, do you think I'm going to die?"

"That's a good question." Bill takes off his hat to scratch the tip of his head. "Do you want to die?"

"N-No!"

"That's swell then! Because I can help you!"

"Huh?" The guy blinks in confusion. "How?"

"It's easy, really." Bill leans his arm over his cane, his single eye seeming to scrutinize the other male's entire being. "I can offer you a deal that you simply can't refuse. I can make sure you live through this and in exchange, you'll let me into your mind."

"What?! No!" The blond quickly shakes his head, his eyes widening at the idea of having someone else take over his brain. "I don't want you in my head! I don't even know what the hell you are!"

"Honestly, I'm offended that neither Stan nor Ford has ever mentioned me after all we've been through." Bill rolls his eye. "But putting that aside, I'm not gonna hurt you, kid. I just need a new friend, that's all. I've been stuck here in Stan's mind for who knows how long. I think I've had enough of his disturbing dreams, thank you very much. Remember that one guy I told you about who volunteered to visit someone else's dream using Ford's machine? I'll drop you a hint," He points to himself, looking cheeky. "that was me. And somehow, I turned into this. There's no way I could ever bring myself out into the real world anymore but the least you could do in order to save my sanity is move me to your mind instead. I'm sure your dreams are far more interesting compared to this old man's. I mean, look at this wasteland!"

The guy looks around again, somehow understanding where Bill is coming from. Stan's dream does look pretty dull. Maybe this is his definition of a nightmare—plain and boring. The old guy creates the impression of someone who prefers to get into a lot of adventures. He and his brother always have stories to tell about their great travels together after all.

He swallows a sigh that burns its way uncomfortably through his chest.

Bill doesn't seem to be that bad of a companion. He talks a lot but he looks like he means well, in spite of the perpetual mockery in his tone.

"Promise you'll keep me alive?" He confirms.

Bill gives him a wink. "I don't back out on my word. Deal?"

"Okay." Finally, the blond nods. "Deal."

Bill's nonexistent grin reaches his eye as he offers his hand, suddenly engulfing it in a spark of blue flame out of nowhere. "Let's shake on it."

The blond swallows the lump stuck in his throat before reaching over and shaking the creature's hand. It feels colder than he thought it would, especially since the blue flame turns out to be very misleading. Before he could have the chance to pull his hand away though, Bill's grip clenches tighter and yanks him closer.

In a deep voice that completely contrasts his usually light mocking one, the creature bellows: "TAG, YOU'RE IT!" His eye suddenly alters to a deep shade of red. The guy fails to grasp the opportunity to actually comprehend what's happening and to react to it as fast possible when warmth spreads throughout his body and he abruptly feels light on his feet. He screams upon catching on the fact he's literally floating in the air, Bill's hand nowhere near his anymore.

In fact, Bill is absolutely nowhere to be seen at all.

But then, standing on the grass remains his own body.

Wait, what?

His body?

He then sees his own head tilt up to look at him, his own lips curling to a shit-eating grin. "See ya, kid!" Bill's voice comes out instead of his and just like that, he realizes that he's no longer in control of his physique.

"Wha-?! No! Wait! What did you-?!"

He fails to finish his sentence when a blaze of light suddenly blinds him.

Bill opens his eyes. His two eyes. Whoa, what a change. He's welcomed by the sight of Ford looking down at him in genuine concern. It doesn't take him more than a second to know that he's in the underground laboratory. He knows this place as well as Ford does—or at least, he used to. Things look a bit different now. The place appears to be newly renovated. The computers, machines, and gadgets… everything looks so advanced.

"Kid, how are you feeling?" Ford's voice cuts through his thoughts and Bill slowly sits up, mentally cursing the damn body he's in for having no strength at the moment. It's like being inside Pine Tree again. Perhaps being a volunteer to Ford's experiment has weighed too much stress on the kid. He lets out a groan, his hand coming up to caress his head. As much as he enjoys the painful ache throbbing in his skull right now, he needs to focus on his surroundings and make sure Ford doesn't detect anything different about him.

The last thing he needs right now is the Pines family ruining everything again.

"My head hurts…" He feigns a wince, his voice coming out croaky with sleep.

Ford gives him a pat on his shoulder. "Don't worry, you did well. Stan's still sleeping peacefully." Bill follows the old man's gaze to see Stan lying on a bed beside his, a silvery helmet settled on his head. Multiple wires could be seen connected to it but Bill has already grown bored of looking at it so he directs his gaze back at Ford. Ford returns his stare. "This is the first time in a long time that he's slept this long. I guess whatever it is you did there, you saved him from his nightmare. You can give me the details tomorrow. I'm sure you're tired."

"Uh… yeah." Bill plays along. "Ooh boy, I sure am tired. I should get to bed."

Ford doesn't seem to notice anything odd as he reaches over to take off the helmet from the blond's head. "Get going then. Mabel woke up just a few minutes ago and is in the kitchen."

"Mabel?" Bill finds himself asking before he could stop himself, his mind immediately looking for a face to put on that name.

Oh, Shooting Star.

Ford seems to have caught on his inquisitive tone though for he looks back at him in slight surprise. "…you're not suffering from memory loss, are you?"

"Nope!" Bill shakes his head, his tone coming out livelier than he intended. "Just… dizzy. Words sink in slower than I like, ya know?"

Ford doesn't look convinced. "Yeah… you do sound a bit off…"

Taking this as a hint to get the hell out of there, Bill jumps up to his feet and dusts his pants. "Well, I'd best be out of your way. I'll go see what Shoo—ahem, Mabel's up to." He doesn't take the bother to wait for the old man's response as he heads for the elevator nearby, content that it's still located where he last saw it. He needs to lay low for now. He can't afford having anyone be suspicious of him. It wouldn't be that challenging to play along with whatever kind of life this body has, right? He just needs to wait a little bit longer for his abilities to come forming back to their full potential. The Pines family are a bunch of idiots if they thought making Stan remember everything will only bring back the sole images of his memories. If he remembers, then it exists.

And of course, Bill Cipher always deems himself as a pretty memorable guy.

When he gets his powers back, he will have them on their knees and groveling for his mercy.

Not like he'd give them any. Or maybe he will, just to get their hopes up before crushing them down again.

Soon enough, he nears the kitchen where the light is on. Through the doorway, he sees a young girl—most likely in her early 20's—seated on the dining chair with a pint of ice cream on the table. Her soft dainty features are painted silver with moonlight from the wide window nearby. Her soft auburn curls appear to be disheveled, as if she had just gotten out of bed. She's sporting a pink over-sized sweater and a pair of men's baby blue boxer shorts, one sleeve of her sweater sliding down to reveal her bare shoulder.

She's eating ice cream by herself silently, looking bored.

This isn't the Mabel Ford is talking about, is he?

For how long had he been in Stan's mind?

As if feeling his stare, Mabel catches his eyes and Bill almost flinches in surprise. Even though the Shooting Star that he knows has grown to an undeniably stunning young lady, she still has that somewhat dorky smile. Bill could only guess that she's an adult now, but she still seems to have the exuberance of youth as she bounces up from her seat.

"Will!" Before Bill could react, she suddenly throws herself in his arms as though that's something she normally does. Which she probably does. "I was so worried! Uncle Ford wouldn't even let me into the laboratory anymore because I couldn't stop fretting over you. I couldn't even sleep!" She pulls back a bit to meet his eyes and Bill has only come to realize that her lashes are quite longer than he thought. "Don't ever do stupid stuff like volunteering in taking part of Uncle Ford's experiments ever again, understand? That's Dipper's job."

Not entirely sure what to say (and perhaps feeling a bit confused as to why their bodies are pretty much pressed up against each other with his hands still on her waist), Bill just shrugs. "Sure thing."

A smile scatters light into Mabel's dark eyes and to add even further confusion to the demon, she stands up to the tips of her toes to plant a swift peck on his lips.

"Good!" She nods in content. "Wanna eat ice cream with me for now before hitting the sack?"

Oh boy.