On account if the fact I have no idea where this story is going, this AU is now free to use (WITH CREDIT). Sorry if you wanted me to finish the story.

/\/\/\

Dipper had always been a pretty normal kid asides from his birthmark and constant hallucinations. Like a couple of kids his age he still had an imaginary friend.

Her name was Mabel Pines. She was Dipper's imaginary twin sister who had a personality (almost) as bright as her sweaters.

It came as a shock to people at first that Dipper still had an imaginary friend; many naturally assumed that was three year old stuff and not really appropriate for a boy the age of twelve. However, the amount of work Dipper had done in forming Mabel's character was impressive. And it was about to get even more so now they were in Gravity Falls.

Dipper wandered about the shack, trying to make sense of all the strange items that lined the rickety shelves. It seemed stupid that people really beleived it was even legal for a guy to sell sereved eyes in jars. Mabel gave him a reassuring smile as they walked on. Quite suddenly, Dipper coughed as the suffocating air of a smoke bomb embraced him.

'Welcome to the Mystery Shack! Oh, hey, are you that great nephew I'm supposed to look after?' A vaguely familiar man said, once the smoke was clear. Dipper only really remembered Grunkle Stan from his childhood when Stan had called him 'dememted' to have an imaginary. Dipper and Mabel just carried on playing with wooden blocks.

Now was no different. Stan was unhappy to hear he still had Mabel. Dipper protectively replied that it proved he was creative.

'Whatever, kid.' Grunkle Stan grumbled. Dipper wandered away from the shack.

'I don't mind, bro. Lighten up!' Mabel said cheerily, pressing the bulb on her sweater so the darkness of the forest disappeared.

'Fine.' Dipper replied. He stopped still in his tracks.

'What is it?' Mabel asked.

'You're in my mind, Mabel. If I knew, so would you.'

'Good point, but what if you imagined me not knowing?'

'Two shay. Come on, let's just go. Probably a squirrel.'

'I'm no squirrel, kid.' A voice said. Dipper looked up to see a floating dorito.

'I'm Bill. You must be Pine Tree. And this is Shooting Star, I presume.' Bill said, drifting close and poking Mabel. It was almost as if Dipper and Bill could see Mabel without imagining her now... perhaps, he thought, I'm just that used to her.

'How can you see her?'

'She's part of the mindscape.'

'So?'

'I can see the mindscape. She only exists within another dimension that contains all items created by the mind, including this imaginary friend. The dimension is almost like an invisible blanket over yours.' Bill explained. 'Humans aren't supposed to know that. Well, time to kill you.' Bill continued.

'I'll protect you!' Mabel said. Dipper looked puzzled.

'Hey, I didn't imagine her saying that!'

'Oh, right. When I touch an imaginary being, I move them to a different layer of the mindscape where creatures are self - conscious. The invisible blanket also lifts and everyone can see and hear the create but not touch them.' Bill replied.

'Why are you telling so much?' Dipper asked.

'Why are you asking so much?' Bill replied. While he was talking, Mabel was able to aim a solid blow in his chest, winding the triange and making him flee.

'I'M FREE!' Mabel exclaimed, running around.

'Hi. Are you, like, the same Mabel?'

'Of course! You didn't think I'd just disappear now I'm in the second layer of the mindscape, did you? I've been waiting years to be touched by a mindscape being!' Mabel blabbered on an on about how she so wanted to actually talk to Dipper.

'Wait a second... doesn't this mean that Bill, that triangle we ran into just then, was actually from someone's mind, and got touched by another self - conscious mindscape being?' Dipper pondered. Mabel was just busy messing around with around with a tree.

'Come see, it's like this tree is metal or something!' Mabel called. Dipper came over. Sure enough, he was able to open a small, rusty door. Inside there was a book. Dipper wiped the dust off a golden hand.

'Three.' He read. The book was a brownish red, with a golden hand in the middle. Written on top of the hand was a large "3". Dipper opened the book. Mabel peered over his shoulder.

'It's hard to beleive that it's been six years since I started recording the secrets and mysteries of this town.' Dipper read. Mabel looked at the inside of the cover.

'Of course, the author's name is ripped off. How cliché!' Mabel complained. Dipper shoved his hand back into the tree and pulled out the rest of the paper. The name was much too smudged to read. Mabel huffed.

'Let's go home.' Mabel said, attempting to grab Dipper's hand. Then she blushed in embarrassment and remembered she was still in the mindscape. Dipper laughed and beckoned Mabel to follow.

/\/\/\

'I don't get it, Mabel. I've always been able to see you without thinking. I thought I was just that used to you, but do you think maybe I have some kind of power?'

'I've overheard conscious mindscape beings discussing that and they always mention a "Chosen boy" and how he can see any layer of the mindscape.'

'Hey, remember that time I was able to imagine and describe that guy's imaginary pet perfectly? And how I always hallucinated when I played imaginary games as a little kid? You don't think?'

'Oh, I think. We have to find that triangle guy and work out what's going on here!' Mabel said, banging her fist on the table. Stan walked into the living room. He dropped his plate when he saw Mabel peering up at him. He looked at the girl in horror.

'She's just how you described her.' He said blankly.

'No time to explain. Me and Mabel got some important buisness to attend to!' Dipper replied.