Petra Pines was reading on her bed when it happened. She lived in a house in the suburbs of Gravity Falls, where she was born. She was the sole child of Dipper and Pacifica Pines. And her life was reasonably normal. Until a demon popped into his room and introduced himself.
It all began when Petra heard the voice. At first, she ignored it, thinking it was a figment of her imagination. That happened sometimes. She would just hear voices with no explanation attached. But she only heard each voice once.
But this time was different. The voice spoke again. It sounded like a boy, lost and confused. "Am I even real?"
"What?" she asked, intrigued that this voice, out of all the others, had called out twice. And it sounded again.
"You can hear me! I'm real!" the voice paused as if contemplating. "Unless you aren't."
"Uh, I'm real. I'm just not convinced you are," she responded reasonably.
The color drained out of Petra's surroundings, and an eye opened in the middle of the room. It was a large, colorless eye with a line for a pupil.
Then the rest of the being appeared, bricks materializing out of nothing and building into a triangle around the eye, with thin arms and legs. A tall top hat appeared above it and a bowtie materialized under the eye. The entire thing was shades of gray, from a black top hat and bowtie to the gray of the bricks to the white of the eye.
The "Being", as Petra was beginning to refer to it as, floated in the middle of her bedroom. There was something distinctly startled in that eye as the Being bowed to her.
"Hello there. My name is . . ." it paused. "Well, I don't actually know."
Petra was startled into falling off her bed.
"What the FLIP?!" she yelled. "What are you?"
"Ha! I hoped you'd be able to tell me!" it replied.
"Wh-what do you mean?" Petra asked, collecting herself.
"I don't remember anything. Only . . . a great battle. Oh, and a pine tree, a shooting star, and a six-fingered hand. Any idea what those could mean?"
"Um, nope. No idea. But maybe Dad will be able to tell you. He does supernatural stuff."
Petra led the Being through her house until she came to her dad's Work Room. She knocked.
"Yes?" a voice responded.
"Dad, I have something to show you," Petra said.
Petra's father sighed. "Petra, you know you aren't supposed to interrupt my work."
"Yeah, but this is important. And related to your work."
"Fine." Some papers rustled inside the room. "Come on in."
As soon as the door opened, the Being recoiled. "Pine Tree."