Only Mabel [A Gravity Falls Fanfiction]

Prolouge

"Who are you?" The girl asked to the man, floating in the black and white room.

The man in yellow replied to her, "I'm just a simple deal-maker, I can do something for you, but you must do something for me."

"So kid," the man in yellow continued, in a different tone, "what does your heart desire?"

The girl was only 5, and didn't know the gravity of what she was about to do.

"I want a sibling. I'm pretty lonely."

"And in return?"

"I don't know. I just want a brother my age."

"How about this. In your proudest moments you will fall, and I'll give you a twin brother."

The yellow man extended his arm, for a hand shake.

"All you gotta do is shake my hand."

She took his hand, and the brunette panicked when it caught on fire. The fire soon dissipated.

She was startled awake.

Was that all a dream? The little girl thought to herself.

She looked to the other side of her pink bedroom, finding another bed, and half of the room painted blue.

That was not a dream. At least not an ordinary one.

The wish-granted came through!

The young girl, had a brother! He looked just like her, as the yellow man had said he would.

Her parents, and everyone else, thought he had always been there.

But the five year old girl knew better. 

The boy was nothing but Magical Energy, manifested into the real world.

Not even her new twin knew he was fake.

The girl soon forgot, too.

She forgot the deal, she forgot about being an only child.

She forgot about the yellow-clad man.

Mabel Pines forgot that Mason Pines was only manifested Magical Energy.

The only mark to say the deal ever happened, was a strange birthmark on Mason's forehead, earning him the name Dipper.