Monsters Within [Complete]

Bodies change kids, bodies change.

"Yaaaawwwn" Mabel had just let out her morning yawn. She tried to get out of bed... and she did, but not the way she expected. She flopped out. She shook her head out of her daze and looked at her legs. She didn't have any. Her legs had been replaced by a fish tail! She screamed.
"Uuuughh" Dipper groaned as he lifted his head out of the covers, revealing two cute fluffy ears.
Mabel couldn't help but stare.
"What?" Dipper asked, still sleepy.
"Your ears! My tail!" Mabel said while stroking her fish tail.
Dipper's eyes went wide when he noticed Mabel's legs were gone! and replaced with a fish tail.
"Mabel?" He said as he started taking the covers off his body.
They both stared at Dipper's lower half.
"AAAAAAAAAAH!" They screamed in unison.
Dipper got out of his bed, trying to stand on his new legs.
"Deer legs..." Mabel whispered under breath.
Dipper was slipping and tripping on his hooves as he tried to walk towards Mabel.
"Ah hah ha" Mabel laughed.

"It's not funny, Mabel!"Dipper said as he face planted the floor.

"Hmmm..." Mabel said as her tail started to itch. While Dipper was getting used to standing with 4 deer feet Mabel asked him:
"Hey bro bro, can you carry me to the tub?"
"I'll try" Dipper said, now able to stand and walk slowly.
Dipper was barely able to carry Mabel with his noodle arms, but was able to make it to the bathtub. Mabel turned on the tub and rinsed her tail. It wasn't itchy anymore.
"Let's go tell everyone how awesome we look" Mabel said while hugging her flexible tail.
"What are we gonna tell..... Stan!?" Dipper's expression showed surprise, shock, a little fear, and confusion as he seen Stan almost bursting through the hallway ceiling. Stan was at the entrance of the bathroom.
"You guys ok?" he said
The twins just stared at Stan. He was huge! and he definitely wasn't made of your usual flesh-and-muscle he looked as if he was made of some sort of stone or something.
"S-Stan wh-what? you too?" Dipper said.
"Woah he's all rocky and stuff and HUGE!" Mabel said.
Stan crouched so he could see the twins. "Yeah, everyone in town is like this, what happened?"

"Everyone?" Dipper and Mabel asked then anxiously looked at each other.

"EV-ERY ONE" Grunkle Stan replied then exited the cramped area.

After taking it all in, Mabel asked, "Hey Dip, take me downstairs!"

After shaking his head from his trance-like state he took Mabel downstairs and put her on the couch in front of the tv.
"I'm gonna take a look around, stay here." Dipper said before leaving his sister, who was watching a marathon of duck-tective.