Because Stan deserves to be in here somewhere.

Consciousness returned slowly but eyes didn't flick open straight away. Stretching the stiffness from each limb before turning around and cracking eyelids open slightly, the other person who usually occupied the area was missing. 'Dipper's probably already up,' Mabel told herself, although she found it slightly suspicious that her twin's bed was already made. Glancing at the clock kept next to Dipper's bed, it was nine o'clock – oddly early for her brother to be up already, let alone have his bed made. The girl got out of bed and fetched a set of clothes for the day: a yellow sweater with a small, blue elephant patch stitched onto it; she donned a blue skirt and brushed her hair before slipping on a matching teal headband. Slipping her feet into a pair of socks and shoes, she ran out the room and headed downstairs quickly, shouting out to her family: "do I smell stancakes?" She sniffed the air and noticed the lack of any sweet, sugary scents or even a greasy stench; what she did notice, however, were the hushed voices emanating from the kitchen that seemed to grow quieter as she descended the creaky wooden steps. Undeterred by the hushed echoes, she ambled into the kitchen quickly with a large smile.

"Hey, sweetie," Stan greeted as she entered, "you're up early."
"Mm, what were you both talking about?" her eyes scanned the older twins curiously.
"About the gift shop, adult stuff," Stan replied before Ford could give an answer.
"Where's Dipper?"
The two men exchanged worried glances before Ford spoke: "He's gone out with Bill again."
"This early?"
"Yeah. So, uh, your dentist thing is today, right?" Stan asked, scratching his back lazily.
She grinned, "yeah, it is. It's soon actually… ten o'clock, I think?"
"I'll take you to the dentist, then," Ford concluded and clapped his hands in a hurrying gesture; "be quick, it's not long until you have to go."
"Ok," she sat down at the kitchen table and waited patiently, humming and swinging her legs idly. The room was engulfed in a comfortable silence as Ford sat down, too and took a swig of coffee while Stan stood over the cooker, making some pancakes. "It'll be weird without my braces," Mabel mused in an attempt to start a conversation.
Ford only hummed his acknowledgment, taking another sip of his coffee while his brother replied: "how long have you had them in now?"
"More than a year now."
"Yeesh, must've had some pretty bad teeth, kid," he chuckled and she laughed, too.

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Soon after the girl had finished her pancakes – which Ford had commented were rather sugary considering she had to visit the dentist soon – she cleaned her teeth and stood by the door, ready to leave. Ford slipped back into the house and was about to whisper some quiet words to his brother but was interrupted by the other man; "yeah, I know. I'll keep an eye out for the kid," Stan reassured.
"I would look for him myself, but… I'm the last person Dipper would want to talk to right now," Ford frowned.
"Don't worry, I'll find 'im."
He looked like he was about to reply but a shout from the other room interrupted him: "Great Uncle Ford, come on!"
The men nodded to one another in silent fare wells before he left to take Mabel to the dentist.

Stan sighed as the door closed behind them, massaging his temples with his thumb and index finger. "Just what have you gotten yourself into this time, kid?" he asked to no one in particular. Heading into his dark office, he opened the blinds in the room and an array of bright light lit up the dull room; he squinted at the sun that shone in his eyes, turning around and ignoring the bright splodges that lingered in his field of vision. He left the office ten minutes later clad in his usual suit, a dead-serious expression etched on his features and a baseball bat in hand. It was better to be prepared with some sort of defence than to go empty handed and in danger; he wasn't a stranger to all of the worrying monsters out in the forest, he knew that it could be dangerous. Silently making his way through the building, the man exited through the front door of the shack, making sure that the sign was flipped to 'closed' and the door was locked. Tapping the end of the wooden bat in one hand, Stan gave a brief sigh before setting determined eyes on the forest. It was time to search for Dipper.

Briskly entering the forest, Stan stepped over each and every root and rock easily – he ventured the forest quickly but thoroughly in search for the younger boy, checking each clearing and behind every tree big enough to hide behind. After a long hour of searching, the man stood in the middle of a small, empty clearing; he sat down in the middle of the space and rubbed a hand over his face tiredly. "Where could he have gone?" he muttered to himself.
"Hey," a quiet voice breathed in his ear and he whipped back around instantly only to find no one there – the voice had sounded just like his grand nephew's.
"Dipper?" he asked warily. "Kid, are you there?" he stood cautiously and scanned the area in front of him.
"This way," another childish voice whispered in his ear from behind him again and he whirled around fast enough that he almost lost his balance.
"Kid, where are you?" he asked and scanned the area once more. His eyes stopped over one tree when he saw a dark shadow moving through the trees quickly, away from him. "Kid!" he called after it and quickly ran after the shadow – it was Dipper; he was sure of it. It sounded just like the boy, and the short glimpse he'd caught of the other looked just like him.

Running through the thick crowd of trees, he desperately tried to keep up with the smaller boy but could only watch as the young teen ran faster, putting more distance between them and losing him in the forest. "Dipper!" he called after the other again, "stop running!" he panted and was forced to slow as exhaustion got the better of him. As he slowed down, he noticed the brunet stop, too, feet skidding to an instant stop; but he didn't turn to face Stan yet. "Kid," the man panted and leaned on a nearby tree for support, "what- why are you running?"
The boy slowly turned to face him to reveal an uncharacteristically large grin stretched across his face and typically warm, chocolatey eyes were instead a dark, murky black. Dipper's familiar voice whispered in his ear again and he tensed; "this is fun," it spoke nonchalantly.
"Dipper…?" Stan asked warily, fighting the urge to turn around.
The other only released an odd, high-pitched giggle before spinning around and darting behind a tree again.
"Kid, stop running!" Stan shouted after him but followed swiftly.
"Only if you catch me," the voice whispered in his ear again; he had a sneaking suspicion that his nephew was being manipulated, or perhaps that it wasn't the boy at all but something that had taken his form. In either case, it meant that something bad must have happened to Dipper.

This time, as Stan chased Dipper through the forest, no distance was added between them – the boy didn't bother to run fast enough the lose the man, as if thinking of it as a game. So close yet still too far away, the brunet occasionally glanced back at the man with a grin still etched on his features and a playful gleam in his eye; another laugh soon bubbled up from the thirteen-year-old's chest as he brushed his palm against a tree that he passed. The already rotting bark of the tree seemed to quickly rot more and faster and the tall figure of the plant collapsed at the weakened state of the wood: it collapsed immediately and fell in the pursuing man's path. However, he dropped the bat he'd been carrying and easily lifted himself up on his hands and swung himself over the obstacle, jumping clean over it to continue running without losing any speed. "Dipper!" he panted again. "Is-" he swallowed, "is this that demon controlling you?!"
A louder laugh rang through the air at the question as if he'd said something funny. Dipper's hands lit in dangerously red flames before he brushed each palm over another two trees either side of him, still running as he did. Between the opposite trees, a line of fire quickly arose and blocked Stan's path. Instead of stopping or recklessly jumping through the scorching flames, he diverted to the right and quickly moved around the tree to continue on his way, pushing himself faster and harder than before in an effort to catch up to his nephew.
The brunet seemed to notice the closing distance between them and the grin dropped instantly as he pushed himself faster to gain the lost distance back again.
"Stop! Give the kid his body back!" Stan shouted, now certain that Bill was controlling the boy after the show of fire. The endeavour to catch up quickly became a lot harder as they reached a hill; but he followed the boy up the steep slope, still. He was determined to catch the brunet if it was the last thing he did. They soon reached the top of the grassy hill after a few long minutes, a couple more metres having been put between the man and the boy. The brunet stopped at the top of the hill while Stan continued to run toward him – he turned to face his Grunkle with a newfound playful smirk upon his face and only then did the older man notice the cold steam rising from his nephew's hands, which were laced with a freezing ice. Just as he was within arms-length of the other, Dipper knelt down quickly and planted freezing hands on the floor, fingers digging past the lush grass and into the mud. The next step Stan took was his literal downfall; the ground beneath his feet had been encased in a slippery layer of ice and as his foot hit the surface of it, it slipped forward and he tumbled backward to land on his back, knocking the air from his lungs harshly. He scrambled to get his feet beneath him again but could only watch as he slipped away, back down the hill, his eyes fixed on his grand-nephew who stood atop the tall hill with a grin planted firmly on his face.
Dipper's voice whispered in his ear again as he reached the bottom of the hill, scrambling desperately to his feet: "you weren't planning to hurt your own grand-son were you?"

That was when it clicked in Stan's mind. This wasn't Dipper or Bill – no, it was just another monster imitating his nephew, making wrong assumptions on who the boy was to him. The man wasn't sure if he should be relieved or not. He simply glared at the creature before turning around with a dismissive wave of his hand. "Is that it, gramps?" the voice laughed in his ear again. "Giving up already?" He ignored the voice and started walking away, only to be interrupted by the voice again; however, this time it rang loudly from the imitator's mouth rather than the air next to him: "Oi, don't ignore me!" it shouted angrily, still in Dipper's voice. The creature ran down the hill quickly, grin replaced with an irritated scowl; as it reached the bottom of the hill and approached the other, it jumped onto his back, wrapping small arms around his neck and legs around his waist. Tugging on the elder's hair harshly, it complained: "I'm lonely and bored so don't ignore me."
Stan yelled at the being angrily, "hey, get off!" he reached back in an attempt to grab a hold of the being but found that he couldn't reach at such an awkward angle. "Go bug someone else, y' freak!"
"Imp, actually," it scoffed.
"I don't care," he yelled and finally managed to throw it off of his back. "Get lost."
It glared at him as it landed, rubbing at its elbow. "You were the one chasing me," it argued.
"Because you look like my grand-nephew!"
A smile spread across the imp's face at that statement. "Your grand-nephew? What say you that I help you find him?" he stood – still in the form of Dipper's body – and looked at the other.
"I said get lost," Stan pushed past the imp and stormed off into the forest. The imp was quick to follow.

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A content sigh was released but chocolatey eyes didn't flutter open just yet; rolling onto his side, he inhaled a crisp smell deeply through his nose and breathed out through his mouth while allowing a smile to tug at the corners of his lips. Something soft tickled the expanse of his skin softly and a welcoming warmth wrapped around his body; wind gently caressed and played with his messy, chestnut curls of hair and quietly rustled the blades of grass below him. Eyelids finally sliding apart, Dipper rolled over again to lay on his back and admire the blue sky above, blocked only by the few emerald leaves that swayed slightly in the wind.
"Hey there, Pine Tree," a familiar voice filled the air and the boy let his head fall idly to the side so he could look at the other.
"Morning," he replied.
"I think you mean 'afternoon,'" Bill corrected.
"Did I sleep for that long?" the teen sat up and stretched his arms above his head, back arching and toes curling pleasantly as he got rid of the stiffness in each limb.
"Yup; you have a nice dream?"
Shrugging, he leaned back against the thick tree trunk behind him before answering, "I don't know, I already forget it."
Bill rolled his single eye in boredom, "you meat-sacks and your terrible memory. We should really fix that sometime."
"Mm… I should probably head back to the shack soon," he frowned at the thought.
"What's the rush, kid? Why not hang out here for a while longer?"
"I don't know, everyone's probably worried about me…"
"Let them worry, what have they ever done for you?"

Eyebrows furrowing at the statement, the boy quickly defended his family: "they do loads of stuff for me. I don't want them to worry because I'm back so late," he tried to stand but was pushed back down by a sudden burst of magic from the demon.
"Like what?" the immortal asked. "They just keep trying to mess things up for you, kid. Do you really want them holding you back from doing everything you want to do? Think about it, all of the times that family of yours has betrayed you – they don't even trust you."
"They do… they trust me," he defended.
The immortal rolled his eye again with a scoff; "looks like you don't know what trust means, Pine Tree. Your entire family was working to get rid of me behind your back even though you told them plenty of times not to," he gritted the words out with clear restraint. "I don't know about you, but that doesn't sound like trust."
"They just don't understand. They… they think they're helping," his eyes darted around the space, avoiding eye contact with his demonic companion.
"Don't be so sure. That's not the only time; Fordsy wouldn't trust you near any of his things-"
"He's like that with everyone," Dipper argued.
"Fez spent nearly an entire summer lying to you about who he is," Bill carried on as if the boy hadn't said a word.
"That was to get Great Uncle Ford back, everything is fine now," he countered again urgently.
"Even your own sister trusted him – a complete stranger – over you, ignoring what you said and putting everyone's lives at risk."
"She… I…" the boy stuttered, desperately searching his brain for some kind of excuse or defence for his twin.
"Face it, kid. Your family doesn't trust you."
The boy didn't reply, he only pulled his knees to his chest and wrapped his arms around them silently, looking down at his lap. The demon's words echoed through his mind. Was he right? Did his family really not trust him?
"Your family doesn't trust you at all, can you really trust them, either?"
Eyes flicking up to look at the immortal, he didn't know what to say.
"Trust me," Bill coaxed.
"I…" looking into the singular, large orb, he said the only thing he could think of: "I do trust you."

The statement hung in the air for a moment where neither being spoke, until Bill finally did. "Pine Tree," he said; "I need you to do something for me." The boy didn't reply so he took it as a sign to continue; "a physical form – I need one now."

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Stan moved through the trees cautiously, trying his best to ignore the comments from the imp that had followed him: "so yeah, us imps can control temperature and stuff. That's how I used the fire and ice and stuff earlier when you were chasing me," it explained – it was still in the form of Dipper's body.
"I don't care," Stan ground out irritably.
The imp stopped in his steps then and for a moment the man thought that his words had finally gotten through to the creature. It seemed to be listening for something intently and paled only a moment later, "wait," he instructed.
"Nope," the other grumbled and continued walking.
"There's a demon that way, you don't want to go there."
He stopped at that and turned to face the creature, raising an eyebrow. "A demon?"
"Yeah. They're bad news, you shouldn't go that way."
"Well then that means I'm headed in the right direction," Stan concluded and turned to walk again.
"You're looking for a demon? Do you have a death wish?" the imp quickly moved to walk alongside him as he questioned the other.
"I'm looking for my nephew. He's with that demon."
The imp stopped again but Stan kept walking. After a moment of walking in silence, he turned around to search for the being only to find the area void of animals. "Must've gotten scared. What a wimp," he grumbled to himself. Suddenly, he perked up as faint voices reached his ears.

"I… I do trust you," it said – it sounded like Dipper.
"Cut it out," he demanded to the imp that had accompanied him.
"Alright," the voice came again and he briefly thought it was a reply to what he'd said before it carried on: "how do I do it?"

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Dipper accepted Bill's request immediately. "How do I do it?" he asked.
"There's more than one way to do it, actually. I'll let you pick how you do…" Bill explained. "The first is pretty fun, actually. You have to gather a whole bunch of organs and flesh and limbs from different places and bring them to a certain place; you can take them from dead or alive people, it doesn't really matter-"
"What's the other way?" Dipper interrupted him, already deciding that he didn't like that plan.
The demon laughed openly, "The more efficient way!" he proclaimed happily. "It'll mean I won't need to constantly fulfil your pointless human necessities all of the time, no food or bathing and no need to deposit my excrement everywhere I go," he pointed out happily. "Your soul."
"My soul?"
"Yup," he popped the 'p'. "You give me your soul and I can mould it into a physical form. What do y' say, kid?"

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Stan ignored the imitations and moved further through the forest, but with each sentence he heard he became more and more convinced that it wasn't a trick being played by the imp.
"My soul?" Dipper's voice asked. He paused for a moment before speaking again, "would it… hurt?"
Was he only hearing half of a conversation?

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Bill paused and his eye flicked to look at the forest around them before he gave a mouthless smirk. "Well, looks like Fez decided to join the party," he muttered to himself.
"What?" Dipper asked, clearly having misheard the statement.

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Stan paused in his steps as another voice joined Dipper's.
"Nah, you won't feel a thing, Pine Tree. You won't even notice it missing," the second voice spoke. Stan hurried to move faster through the trees, now convinced that it really was Dipper and he was with Bill.
"It won't change anything else will it?" Dipper asked unsurely. Stan broke into a jog at the question; what were they talking about?
"Nope."
"So… just my soul? And then you get a physical form?" Stan started sprinting then, desperate to reach the duo before anything bad could happen.
"That's right," Bill confirmed.

Stan finally saw the edge of the treeline, finally reached the clearing – as he burst out across the border, he spotted Dipper with his hand outstretched to the triangular, yellow demon. "Deal," Dipper agreed. Bill reached out a hand to shake when Stan shouted:
"Stop!"
His nephew's head whipped around to face him instantly, a look of pure shock etched on his features. "Grunkle Stan?" he questioned. Bill, however, ignored him. Small palm lighting up in a cerulean flame, the demon moved his hand forward and took the boy's in it; "Deal," he said.

Dipper collapsed instantly, body falling limply to the side and eyes fluttering closed. "Dipper," Stan called worriedly and tried to run forward to help the brunet, only to be forcefully shoved back by an invisible force and knocked harshly into a tree. Head hitting the solid wood of the trunk behind him, his vision swam and a dizziness overwhelmed him; he dropped to his knees, placing his hands on the floor to steady himself and trying to focus on the fingers only to find that instead of two hands, he saw four. Glancing up and ignoring the pounding in his head, he watched as a golden tornado spun and centred around a single point, strands so thick that he couldn't see what was in the middle. The gold was the last thing he saw before he blacked out.

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Light. Not the sort of light a bulb or the sun might emit, but the sort of light that made him feel empty – that was how he felt. Empty. Empty and light. It was different from usual – not to say that he focused on the feeling often… It was such a distinct feeling that was so clear and unusual yet could only be described in those two words: empty, light. He hadn't experienced the feeling before, he knew that much – he was used to the heavy weight of his body and the various organs that filled it, but then it had been ripped away in a quick move. But it didn't hurt. And he was at least seventy-two percent sure that he still had all of his organs…

"Pine Tree~"

A voice filled his head and he had to wonder who it belonged to; was it his own? No. He didn't imagine himself sounding so… odd.

"Pine Tree, wake up."

There it was again. Was he… a tree? That didn't make sense, he knew he wasn't a tree. But then again, how could he be so sure? Who else could he be? Suddenly, he felt like he was falling; despite the infinite blackness surrounding him, he felt a pull on his being that forced him away and he hated it; he yelled at the feeling, desperate for it to stop.

"Pine Tree."

His eyes snapped open and he shot up with a loud shout.
"Finally, you're awake. I was starting to think you'd died for a minute there, kid," a voice laughed.
The boy found himself leaning against the thick trunk of a tree and pushed himself up uncomfortably. "Pine Tree?" he asked and looked down at his hands. "I'm not a tree," his brows furrowed in confusion.
"Oh wow, that really messed you up, didn't it?" the voice laughed again. "Don't worry, it's only temporary."
He finally looked up at the figure that crouched before him. "Bill?" he asked.
"The one and only," the man replied. "Now with a physical form," he smirked.

Imp on Wikipedia: wiki/Imp
Imp BA: (No point in doing this.)

BAM! Who expected this? (Probably a few of you. Congrats if you did.) Next chapter, you'll get to read Bill's physical form's description. Sorry for any mistakes by the way, it's 2:30 AM right now for me and I'm really tired. I think I'm starting to see things from lack of sleep (I keep thinking I see things out of the corner of my eye but when I look nothing is there... Either lack of sleep or my house is haunted.)
And I am SO sorry this took so long for me to update, I have no good excuse. Honestly, I bought a pair of white canvas shoes and was busy painting them to look like Gravity Falls shoes, so I wasn't writing. Sorry, but now they're done and they look so awesome! I have one shoe for Dipper and one shoe for Mabel and on the tongue thingy inside I have a little Bill hiding xD I wish I could show you all.

No plan, sorry. Anyways, I is going to sleep in ma bedz xx

Thanks for reading, please review if you're happy that Bill finally got his physical form! (21 chapters in...)
Feel free to request any creatures or whatever.