Dimensional Rifts! A Star vs The forces of Gravity Falls fanfic

POV STAR
"See," I bend down to Marco, "told you I have a plan."
"Uh," he gets up slowly, "everything hurts."
"Sorry. Next time I'll make us land in a bowl of maple syrup! Oh or maybe a strawberry short cake! Or Jell-o!"
"No." Marco coughs. "The ground is much better."
"Aw." I sigh, "but Jell-o's the best thing about this Earth!" Pause. I look down at a dirty and frustrated Maci rising from the ground. "Besides you, ya know. But you aren't exactly sugary and jiggly and you don't taste good with whipped cream. I don't think so, anyways."
Marco rolls his eyes until they dilate to behind me. "Uh," Marco's eyes grow big, "Star?" He points behind me. I jump and spin around, wand perked, ready for some monsters.
But all I see are two kids and a man.
"Oh," I put my wand away. "Hi." Suddenly, an ear splitting beeping rings through the air.
"Hey!" Marco covers his ears and I do the same.
"What is that!?" I think. I watch as the man brings it closer to me, the beeping getting quicker and louder. He holds it up to my face and I cross my eyes to see it.
"It's impossible." He mutters.
"ITS ALSO LOUD!" I scream at him. He clears his throat and puts it away. He has a slight beard and broken glasses. Not to mention a ratty over coat and a turtleneck. Weird attire for summer. The kids behind him don't look like him at all though. One is wearing a baseball cap with a pine tree on it and a blue vest and the other has a beautiful star clip in her hair and a unicorn t-shirt with an 'x' through the unicorn. I was a bit offended.
"Who are you guys?" Marco asks.
The girl walks up to us, "I'm Mabel. But you can just call me tonight!"
Marco coughs awkwardly and stares at me for help. I smiles and he turns back to the kid, "Well I'm Marco."
"Mabel." The boy face palms. "Flirting? Now!"
"Well I'm Star." I walk away from the man and stand next to Marco.
I watch as Mabel's eyes grow big.
"Oh boy." The boy groans.
"Are you two..." She takes an embarrassed step back, "... Dating!?"
My cheeks turn red and Marco and I stare at each other.
To my relief, he laughs.
"No." He shakes his head, more serious. "We just live together."
"So your brother and sister?" The boy asks.
"No!" I say. "I'm a magical princess from another dimension staying at his house an exchange student!"
The Mabel gasps, "Did you say magical!?"
"Yep." I take out my wand. "I can do all sorts of magic with this bad boy!"
"That's awesome!" Mabel walks up and touches the very lethal object.
"You can also do all sorts of things with your dimensional scissors." Marco nudges me. "Ya know, the reason we came."
Mabel knits her eyebrows at me but I just smile and shrug it off.
"So what bring you to Echo Creek?" I ask.
"Star... Scissors!" Marco taps his phone screen to show the time. I laugh and turn back to the family, I guess.
"Just some saving the world stuff." Mabel pretends to be casual but she fails miserably.
"Mabel!" The man in the inappropriate summer attire exclaims. He looks from me to her, but stays silent. He never denied it, either. All he did was grab the flirty girl and began to whisper to her.
"But I feel like we should help!" I his per to Marco.
He rolls his eyes, "this is clearly a family thing. We should just get going. Grab the scissors and let's go to the dimension I found!"
I sigh, "Okay. I'll be right back." I walk away.
"DONT BREAK THE LOCKER!" Marco yells after me, "it's after school and we can't let them know we were here."
"Ok Marco." I snap, "I'm not a kid I know what to do."
"I know." Marco shouts.

POV MARCO
Dipper and his Gruncle (???) discuss something in quiet frustration and Mabel slides back to her place next to me.
"I really hope Star doesn't break her locker." I say, making awkward small talk.
"Does she... Do that a lot?" Mabel asks innocently.
"Yeah I guess. I dunno she has this spell that makes this bull-guy appear and he's kinda chill but, the principle is mad at me about how much she's broken in the last year."
"Wait why would he be mad at you?"
"I'm sorta responsible for Star. I don't know what I'd do if anything happened to her."
"Oh." Mabel's permanent smile seemed to fade.
"Yeah..." I agree, awkwardly swinging my arms. I look and see a quick shape stand in front of the RV door and quickly disappear. Excusing myself, I follow it in to see Dipper and the old man in the RV arguing.
"Dipper I don't get why you are so upset about this!" The man yells.
"Because you all treat me like a child! I've battled a shapeshifter, a gnome army and I once even decapitated a wax version of Larry King! But yet I'm still a child."
"Dipper you are a child!" He yells.
Dipper looks angry, "NO IM NOT! People have said I am very mature for my age, why can't you see this!"
For some reason, I stay on the steps even though I should probably respect there privacy.
"Dipper," he sighs with a pained look in his eyes, "I call you a child because I don't want to see you throw it away like I did."
"Huh?"
"I regret being so focused on my work, I never had the opportunity to be a child." He smiles a bit. "You have the rest of your life to grow up, don't worry about doing it right now." 
Dipper let's a long breath out.
"When you're ready, come outside." He gets up and I fall out of the RV. As the guy approaches the door, I pretend to wonder back in.
"Hi." I say innocently to the man.
"Hello?" He says curiously. I climb the steps and slide in next to Dipper. 
"Hi." I say again.
"Uh... Hi?"
"Oh yeah I guess this is a little awkward seeing that we just met and all. But Star is taking s long time and that girl Mabel is weirding me out..."
"Mabel is my twin." Dipper states.
"Oh!" I turn red, "sorry I didn't... I mean I... Uh... You guys are so different I didn't notice..."
"It's cool dude." Dipper looks at his feet.
Silence
"So you're saving the world?" I say, breaking the silence.
He nods.
"From?"
"A monster?" 
"Cool cool. Star and I always fight monsters. It's cool, she hits them with her rainbow spells and I like punch and kick them. It looks a lot cooler than how I described it trust me."
"No it sounds like fun," he mutters, "I never expected this town had monster in it."
"Not exactly." I smile innocently, "they come through portals from another dimension and try to take Star's wand."
Dipper looks at me, startled, then turns away without saying anything.

POV DIPPER
I sigh. Marco was actually a cool guy and I need to make more friends closer to my age. Honestly, that's never been a concern of mine, friends haven't been my strong suit. But Ford's little speech was getting to me.
"I uh... Excuse me for one second." Marco gets up, almost shaking. He walks to the front and leaves the RV. I stare out of the window to see he's not standing on the side with Mabel or even Star. I open the window, fresh air always helps while eves dropping.
"Hey," he kicks a rock. "How have you been?"
"Is this guy is insane or something?" I chuckle to myself. "Why is he talking to himself!?"
Silence.
"Yeah." He spins a little, "you of course know I how've been. Right?"
Silence.
"Ha ha ha." He says sarcastically to air, "Shut up."
Silence.
"Listen I'm trying to help this kid. So if you could just stay back there for a little bit-"
Silence.
"Seriously? Just until I'm don't talking to the kid."
Silence.
"Wait what?"
Silence.
"Pine Tree?"
"Pine Tree?" I repeat, a big red flag waving in my head. "No way!"
"Are you serious?" He makes a face at the nothing that was definitely something.
Pause.
"This will turn out even better now! I can't believe out of all the towns in the world, your little friend ended up here."
"Little friend?" I push on the glass in frustration, "even Bill thinks I'm a kid!"
"Oh okay."
Pause
"I totally trust you, shut up." He brushes his hair behind his ear.
"Hey," Marco walks into the RV and sees me on the floor, "sorry, didn't mean to scare you before I got a little sick-"
"You made a deal with Bill!" I point a finger at him accusingly.
"Wait, Bill Cipher?"
"Yes Bill Cipher!" I shout, "What!? Do you want the world to end!?"
"Woah dude." Marco holds up his hands innocently, "I just wanted to get a few powers. Bill's a nice guy, he doesn't want to destroy the world or anything"
"Bill is not a nice guy!" I respond, Marco takes a few steps back. "He's not kind or nice or any version of that world! He's cold and evil and-"
"Now that..." Small laugh. "That hurts my feelings, old friend."
"What-!?" I gasp. Marco looks up, his eyes burning yellow with black slits. He grabs my shirt and holds me in the air inches from his face.
"Hello Pine Tree." I can hear his voice sounds like Bill's, "It's been a while."