Chapter one

The sun was rising over the town of gravity falls, Dipper Pines woke up but something didn't feel right. He didn't feel sick, he moved just fine, what was wrong? Dipper got out of bed and heard a little clip clop, like the sound of hooves. "What?" He looked at his legs and screamed, the bottom half of his body was replaced with the body of a deer! "Mabel! I-" he looked over and saw Mabel flopping around in bed gasping for air. Dipper ran, or technically stumbled, over. Mabel's blanket fell off, she was a mermaid! Dipper screamed again "don't worry Mabel! I'll go get you some water!" He scrambled off to try to get water before he heard laughter. He looked over and saw Mabel laughing. "I don't need water you goof!" She laughed.

"But you were..."

"I was faking it!"

"So you're alright?"

Mabel calmed down, "of course, but I might need a cup of water because my throat is a bit dry."

Dipper grabbed his journal and flipped through it, looking for information as to how this could have happened. Mabel was flopping out of bed and looking for her pig, Waddles. Once she found Waddles, she looked at Dipper. "Did you find anything yet?"

"No, I can't find anything. This is so weird, how could this have happened to us..."

"What if it didn't just happen to us? What if everyone in gravity falls was a monster?"

"Mabel I highly doubt that everyone in gravity falls is a monster."

"You don't know, it could happen. We could call it monster falls!"

"Mabel i-"

Suddenly a loud old man voice came from downstairs, "Kids! Come eat your breakfast!" Dipper nearly dropped his book. "Oh no! Grunkle Stan! He can't see us like this!" He looked at his deer body and stumbled around. Mabel looked at her tail, "we can barely even move, how can we even go down the stairs? Plus, Grunkle Stan will have to find out about this sooner or later. Since he helped us with those zombies, maybe he'll help us with this..." she smiled "maybe we could even be attractions in the Mystery shack!"

Dipper sighed and stumbled over to the stairs. "It's now or never..." he sighed as he took a small step down the stairs. So far so good, he took another step and another until he heard Mabel scream. She fall down the stairs and onto Dipper, causing them both to tumble down the stairs. They fell onto the floor and stayed down, they were in some serious pain but luckily nothing was broken. Footsteps came close to the two, Dipper scrambled to get up. "Kids." Grunkle Stan walked over, his skin was grey and rock like, his teeth were sharp and pointed, his shirt was ripped and he had large wings. "Care to explain what's going on?"

((Author's Note: I only heard a bit about the AU and I apologize if this is inaccurate to the original story. I thought this would be fun to make, so once again I apologize if it is inaccurate.))