The only successful way to describe Mabel's history class is that it was led by that one teacher; no one liked her for her switches between being pleasant to everyone and hating the ground they walked on.
"Okay, class. Now that everyone's here, maybe we can begin our introductions." The teacher said through chair-squeaks. "You may call me Ms. Cantaloupe, and that will be the only way you shall address me. Not Mr. C, not Ms. Can't." She looked at the closest desk in the row.
"You there!" she said, pointing at the confused child. "What is your name and something interesting about your summer?!" the child rose.
"Uhhh...hi. My name is...uhhh...Butch...?"
"Okay, Butch. Now tell us what you did over the summer." Ms. C said, writing something down on a clipboard.
"I...uh...worked out a lot..." Butch said, searching the room for any response other than the occasional cruel snicker.
Mabel refrained from the herd's mentality, choosing instead the path of comfort. By some chance, the only open seats were those directly adjacent to those of Butch (though she had no idea why). Maybe it was like that king piece in chess, where no one else could get within a square of him without facing death. Yeah, that was it! He did seem...awfully nervous, anyhow. Mabel did the logical thing and pat Butch on the back. To comfort him. The smile he returned didn't bode well for the frequency he smiled. It deepened her sadness.
"Thank you, Butch." Ms. Cantaloupe said, finishing her thought on paper. "Now, since you arrived late, you can go, young lady!" She pointed a green pen at Mabel with much enthusiasm and distaste.
"Hi." Mabel said, standing from her chair with less enthusiasm than was normal for her. "My name is Mabel of Dipper and Mabel Pines-"
"Hmm, hmm yes." Ms. C cut her off, furiously scrawling across the clipboard. "And what fun thing did you do over the summer?"
She was annoyed, but nonetheless continued "Mostly antagonist my brother." She was eager to sit back down so the person the class new would be closer to her cheerful self, her true self.
"Okay Mabel, you may sit down." The teacher said. Her next words, and near every word after that, was lost to Mabel, thinking about her stolen gift.
She had her head down thinking about it for the next 20 minutes of class. As much as Mabel would have liked to know her peers, she couldn't focus on them.
"I'm sad to say that we've come to the end of the hour, class. That will be all for today." Ms. C said with a drop of sap. She took a stack of papers from among the sea of others on her desk. "Though I do need you to read this syllabus over and get signed by your parents."
Mabel took the sheet and stuffed it somewhere among her glitter pens. She took a moment to look over at Butch to see him trying to find an unripped pocket in his bag.
She planted her chin back on crossed arms and waited for the bell to ring.
On Dipper's end things weren't much better. His math room, while clean and up to date, had the artificial feeling of a long word that someone thought made them sound smart. The teacher, Mr. Metternich, was nearing the end of his natural life with a bald head that he hid remarkably well with a brown leather hat.
His assistant was the counterpart; Young, spry, fresh our of collage and ready to teach!
Introductions went about the same way as Mabel's. Everyone introduced themselves going down the rows from the left all the way to the right.
"You there." The old man said. He had a bit of vitality left, surprisingly enough. It didn't sound like dust escaping from a leaking balloon as Dipper had half expected. "You!"
"I'm sorry – what?" Dipper said with surprise. Evidently he had dozed off again.
"Stand up and tell us about yourself."
"O-kay." Dipper said in tune with his movement upwards. "My name is Dipper Pines and if any of you meet Mabel Pines, she is my twin."
"Rather anticlimactic, don't you think?" The assistant whispered to Metternich after Dipper had sat down.
Something told him Mabel was down as he never felt like this on a day so exiting. For the next 40 seconds all Dipper did was lay his head on the desk and toy with Wendy's gifted hat.
Until someone strange came up.
Maybe it was the volume, the proximity, or some other force compelling him to pay attention, but when the student next to him stood, Dipper listened.
"Hello to all of you." The boy said, looking around at the tired class. "And good to see so few familiar faces. I don't expect any of you to remember me, so I will tell you my name to be Caesar."
The only thing separating Caesar from the painfully stereotypical surfer dude look was a set of deep sunken eyes and an intelligent, almost (but not quite) condescending tone. His smile was that perfectly suspicious mix of I know whats going on and just as planned. He looked at Dipper with it as he sat down, waiting for their teacher to resume. Dipper turned his eyes away, looking at the front of the room with arms still crossed and cradling his head.
"Meet me at lunch tomorrow at table 6. You'll know why." Caesar whispered to Dipper.
Almost everything else after that mirrored the twins experience of introductions and syllabus distribution.
For the record, OC's are not my favorite thing in a fanfiction if only because they are done incorrectly so often. Then again, I'm a renown hypocrite, so only time will tell if I did Caesar right. Let me know your early thoughts.