Co-written by me and Tabbypie101. We don't own Gravity Falls.
"Is the carpet thing the only thing you can do?" Mabel asked, curiously.
"No, I can cast spells and stuff like that too." Robbie said.
"Can... Can... Can you show me?"
"Sure." Robbie said as he pulled his wand out of his hoodie pocket as he casted a spell that made him invisible.
"Robbie! Where are you?"
"I'm still here." Robbie said as he casted the spell that made him visible again.
"How do you remember how to do that?"
"Years of practice." Robbie said.
Mabel smiled," Is there like this magical circle of death where you keep them all harbored to try to keep them all contained until it explodes?"
"Well sort of, there is this magical ball in the wizard world that contains all of the wizards in the world powers in it. If something was to happen to that then wizards would be powerless." Robbie explained.
"Really?" Mabel asked, concerned.
"Yeah but it's highly unlikely that something will happen to it." Robbie said.
"Ok..." Mabel trailed off.
"Yeah, do you want to come see my wizard's lair?" Robbie asked.
"Sure!" Mabel said, excitedly.
"Okay, come on." Robbie said as he got up and rolled the carpet back up before picking it up and led Mabel back to his house as Mabel took his hand.
-BACK AT ROBBIE'S HOUSE-
They eventually got to his house. Robbie led Mabel into his house and down to the basement. There was a locked door. Robbie unlocked the door and opened it to reveal his wizard's lair.
"Whoa." Mabel stood there in amazement.
Robbie led her in "Yeah it's pretty cool, isn't it?"
"YEAH!... sorry..."
Robbie smiled "It's alright. My dad taught me how to cast spells and control my powers in here." Robbie said as he walked over to a big desk in the middle of the room and grabbed a big book and brought it back over to Mabel "This book has every single spell in it."
"Oh, cool. Can I read one to you and you do it?"
"Sure, it's kind of heavy so be careful." Robbie said as he handed her the book.
Mabel struggled to hold it at first, but finally got hold of it. "Ok, Commakus Pancakus."
"Okay." Robbie said and pulled his wand back out "Commakus Pancakus." He said as a plate of pancakes appeared on the table, next to them.
"Yay." Mabel said, taking a bite out of it," Ok, now McReary Timereary."
"Okay, McReary Timereary." Robbie said as time went back by a couple seconds.
"What's this?" Mabel asked, turning to a page marked 'forbidden'," Ummm... Ok, see the world from a magic time, make it my time?"
"Um that's a forbidden spell. It allows a wizard to turn a human into a wizard." Robbie said.
"O-Oh." Mabel said, putting the book down, awkwardly.
"Yeah, if a wizard casts any forbidden spell without permission from the head wizard, they could lose their powers forever." Robbie said.
"I... I... I didn't..."
"It's okay, you didn't know. Don't feel bad."
Mabel turned back to the other sections," Send me away to laugh and play, make me younger by just a day."
Robbie repeated the spell as Mabel turned 3 and her clothes shrunk with her. She dropped the book.
"Oh no." Robbie said "Mabel! Can you understand me? "
Mabel nodded her head, her curls going haywire.
"Okay, do you remember who I am?" Robbie asked as Mabel thought for a minute before shaking her head.
"Crap." Robbie mumbled under his breath "There has to be a way to reverse this." He grabbed the book and looked for the reversal spell while the little Mabel just sat there confused.
Robbie flipped through the book and when he couldn't find one, closed the book "Crap, this can't be happening, my dad is going to kill me!"
Mabel looked at him and tilted her head in confusion.
"Hey I know this might be hard to understand, but you used to be 13, but I accidently turned you into a 3 year old." Robbie explained to Mabel.
"Ok," Mabel said, smiling, obviously not getting it.
Robbie tried to think of a way to explain it to her. "So... Mabel... um do you remember what a wizard is?'
"Umm... Is it like the really old dudes with the long beards and pointy hats?"
"Well yeah, but we dont look like that though. See you I'm a wizard and I sort of accidently performed a spell that turned you 10 years younger, and the worst part is that I have no idea how to reverse it."
Mabel just stared at him for a minute," I'm three." She said, holding out 3 fingers.
"Yeah, I know. You used to be 13 though." Robbie said.
Mabel just looked at him confused," Owkie... Whose arez yous?"
"I'm Robbie and I'm your... well... your boyfriend." Robbie said, hoping she wouldn't freak out.
Mabel's eyes went wide," Wat...?"
"I know it sounds crazy, but like I said before you use to be 13" Robbie said.
"So I was like a thirteen yea ol pwincess and were my wizard pwince?"
"Yeah I guess you can think of it like that." Robbie said.
"Owkie. I Twink I undystad now."
"Good, but I really need to change you back though, but I don't know how... well I could ask my dad, I'll be in big trouble, but it might be our only choice."
"Owkie."
"Okay he's at work right now, but when he gets back I'll ask him."
"Owkie."
"He won't be back for a couple hours, so what do you want to do until then?" Robbie asked.
"My Little Pony!"
'Oh you've got to be kidding me ' Robbie thought to himself before sighing "Okay, come on." Robbie said as he grabbed Mabel's hand and walked with her upstairs.
Mabel smiled and ran up the stairs still holding his hand as Robbie led her into the living room, turned on the TV, and put on My Little Pony. Mabel stared at the TV watching the show, her eyes not leaving the screen as Robbie sat down next to Mabel. Mabel moved herself onto his lap never straying her eyes from the screen. Robbie smiled the wrapped his arms around her. As she watched the show, she smiled and giggled, clearly enjoying herself. Robbie smiled, happy that Mabel was enjoying herself until eventually Mabel fell asleep.