In The Snake Pit

by procrastinatingpinetree

All Dipper Pines wanted to do was see the creatures under the Great Lake. The large window in the Slytherin common room Wendy told him about was bound to give him the best view without actually diving in. Unfortunately, he was a Ravenclaw. But he has been training under Grunkle Ford the past few summers, and everyone should be in class. It shouldn't be too hard to sneak in. Right?

A.N. First time writing Gravity Falls fiction. Never thought that I'd write some of my own, but I've been craving some Hogwarts AU. Mostly Billdip Hogwarts AU, but that's not how this ended up. Well not unless you squint. This is mostly based off a prompt from tumblr: "I sneaked into your common room because I was curious, and everyone is staring at me because I have a different house's uniform. This is so embarrassing. Can you please pretend to know me?" Maybe I'll write more Hogwarts AU with these Bill and Dipper if this goes well. Hope you enjoy this!

Dipper backed up, nearly falling onto the couch behind himself. He trained under Ford all summer. Sure, the disillusionment charm was something he was struggling with, but last time, he was perfectly fine. Unfortunately, shown by the wand pointed at his face, he must not have been as fine as he thought.

Pyronica let out a little giggle as she watched Dipper's eyes follow her wand. She lazily twirled it around. "What's a little Ravenclaw doing in the snake pit?"

Dipper floundered around for words. Victoria Adams, mostly known as Pyronica, was said to be another Bellatrix. While blood purity was not an issue she cared for, people claimed she was just as wild yet just as loyal as the deceased Death Eater. He had never actually interacted with Pyronica before, and he wished it stayed that way. Dipper did not want to find out if the claims were accurate. "I-I-I-" Why couldn't he wait for Wendy to have time to show him around the Slytherin common room? He just had to be overconfident. The one time he was successful at the disillusionment charm, it did not even last that long. Regardless of his time studying under Ford, there was only so much he could learn in the span of a summer.

Another giggle passed her lips. "I-I-I-" she mocked, a wide grin on her face. "Nothing to say? And here I thought with all the time with your head in the books that you'd be able to form a sentence or two." Another twirl of her wand. "Now what should I do with you?" She tapped a finger on her chin, pretending to think. "Got to make an example out of you. You Ravenclaws might start getting too full of yourselves. A little too much knowledge and you think you can just sneak into another house's common room." She rose an eyebrow, frown suddenly appearing on her face. "Were you planning on trying to get back at us for yesterday's quidditch match?"

Dipper quickly shook his head in response. "No, no, no, no, no. I don't even really like quidditch," he immediately said. The frown did not disappear from her face. He winced when he realized he was talking to one of Slytherin's chasers. "Not that there's anything wrong with quidditch," he began to blabber. "It's just not for me."

Pyronica opened her mouth, about to speak when the two suddenly heard the portrait open. Once again, Dipper internally cursed. It could not possibly be Wendy. No amount of Felix Felicis would allow that to happen. He popped that bubble of hope before it could properly form. She wouldn't be skipping classes during her N.E.W.T.s year. He was doomed for sure.

She turned her head, looking back while trying to keep the brunette in her peripheral vision. There was no way she was going to let him go. But the Ravenclaw was forgotten for a moment when she noticed who came in.

Her eyes lit up up. "Bill," she squealed. "Look who I found trying to get an underground view of the lake." She wildly gestured over to Dipper, who looked helpless at this point. Perhaps he would have had to suffer some boils, pink hair, or some facial features literally rearranged if it was just Pyronica. But with Bill there? He might as well try to break the window that showed the Great Lake and allow the Giant Squid to take him.

Bill glanced over behind Pyronica, chuckling when he saw who it was. He nodded to the other boy in acknowledgement. "Pine Tree."

Pyronica practically skipped over to Bill. "I was wondering what I should do to him. I was thinking maybe turning him into a snake and then leaving him outside the Ravenclaw common room. People wouldn't realize it's him and some would freak over a snake." She grinned. "What do you think?"

Bill's eyes flicked over to Dipper. "A snake?" the blond asked her.

"Of course. He snuck in here. Shows he wanted to be one of us so badly." She threw a smirk over her shoulder at Dipper.

'Please,' Dipper mouthed to Bill once Pyronica's gaze returned to the blond. 'I'll make a deal with you.' Bill rose an eyebrow in surprise. Dipper mouthed that sentence once more to ensure the other understood. Sure the two had few interactions. Sure Bill was usually a nuisance and sometimes was a bit frightening. But Bill was also known to not turn down a deal when he knew he had the upperhand, and this was certainly one of those times. Dipper had no room to negotiate.

Bill smirked as his focus returned to Pyronica. "As fun as that would sound, I'm afraid I can't let you do that to Pine Tree."

Pyronica's expression fell, a pout immediately appearing on her face. "Awww. Why not? We can't just let him go. He snuck into our common room. We can't let him out without doing something to him."

Bill sauntered over to Dipper, placing an arm around the younger boy's shoulders. "It's not like he came in without any help." He ruffled Dipper's hair, taking advantage of the fact that the brunette was unable to wear his favorite hat due to class. "I told him the password."

"What?"

Dipper looked over at Bill with the same surprised expression Pyronica had. The same word nearly escaped his own lips.

"Of course. I told him I'd skip Potions today to help him study for his Divination test, and that we could study here while everyone's out in class." Dipper nearly objected to the statement. No way he would be asking Bill for help, especially when it came to academics. As if reading the brunette's mind, Bill tugged Dipper in a bit closer before the Ravenclaw could open his mouth to speak. "Pine Tree's a bit embarrassed about needing help in a class, much less one that one of his relatives excelled at."

Bill looked back at Dipper, expression becoming apologetic. "Sorry I was late. Couldn't shake off my friends fast enough. I'll be sure to make it up to you." He gave Dipper a soft smile.

Dipper attempted to return the smile though he still looked quite nervous. "It's fine. I understand."

Pyronica still looked at the two with some suspicion. "You've been trying to get that little Ravenclaw to yourself forever, Bill." Her gaze flickered over to Dipper. "I get he wants everyone to still think he's some know it all-all Ravenclaws seem to-but I thought you would have told someone." She pouted. "Don't you trust me?"

Bill chuckled and rolled his eyes. "With a prank? Sure. With a secret? Not at all."

Her lips twitched upward, trying to keep the frown. "I guess." She shrugged. "Well I'll leave you two to your studying. I got what I needed anyways." She patted her book bag. Her gaze returned to Dipper. "Say something next time, Pines."

Dipper have her a stiff nod. She responded with a large grin before flouncing away and out the portrait.

The brunette let out a heavy sigh. "Thank, Merlin," he muttered.

"You mean 'Thank, Bill'," the Slytherin retorted, letting go of Dipper.

Once again, Dipper found himself nodding. "Right. Thanks for that."

"So what were you doing here?" Bill asked, "I doubt Red would tell you to meet here. She has N.E.W.T.s this year, doesn't she?"

Dipper rubbed the back of his neck nervously. "Wendy promised she would let me in the Slytherin common room so I can see under the Great Lake so I could observe the creatures in it without having to go in the lake. She's been busy, but I studying under my great uncle Ford over the summer to get ahead in my studies. One of the last things he taught me was a disillusionment charm." He glanced down at his scuffed shoes, shifting his weight from one foot to the other when comparing his scuffed up shoes to Bill's pristine and shiny ones. "I thought it would be the best time to come here since everyone would be in classes." Unconsciously, he ran a hand through his hair, accidentally giving Bill a peek of the birthmark he usually tried to hide. "I guess it wore off when I was taking notes, and I didn't notice. Pyronica came in when I was distracted."

Bill was silent for a moment before bursting into laughter. "Of course that would happen to you," he managed to say between laughs.

Dipper glared at the blond as he doubled over, unable to stay upright. "Hey, it's not that funny."

Bill shook his head, beginning to gain back oxygen in his lungs. "Nah, it definitely is." He stood straight once more, the grin not leaving his face. "You're lucky I decided I wanted to ditch Potions for a nap."

A bit of hope bubbled in Dipper. "So does that mean we can talk about the deal later?"

Bill shook his head. The urge to wipe that grin off the Slytherin's face rose up in Dipper. "Nope," Bill responded, popping the p sound. He grabbed onto Dipper's wrist and dragged the brunette towards the stairs, leading to the boys' dorms.

"Where are you taking me?" Dipper sputtered.

"My room of course," Bill answered nonchalantly. "I did say I would study with you."

Dipper tried to pull out of Bill's grip. "But that was a lie." Damn his noodle arms. Maybe he should have played more quidditch with Mabel when she wanted to practice instead of reading.

Bill's grip tightened. "Well we don't want her to come back and find that out." Bill tugged on Dipper's arm as they made their way up the stairs. "Come on, Pine Tree. Don't drag your feet. I will carry you."

Dipper huffed and did as was told.

Surprisingly this didn't satisfy Bill. "Damn. Was kind of hoping I'd have to carry you."

Red blossomed across Dipper's cheeks. "Sh-shut up."

Bill chuckled. "Maybe later. I am still tired from yesterday's party after we beat you guys."

Dipper rolled his eyes. "You're not going to rile me up that way. I didn't even go to the match," he admitted.

"You have no house pride, do you?" Bill threw open the door to the sixth years boys' dorm. He let go of Dipper and motioned for the brunette to come in first.

Dipper rubbed his wrist and cautiously stepped in. "I have house pride," he objected. His voice then began to falter. "I just don't really like quidditch." Awkwardly, Dipper stood in the middle of the room, unsure where to place himself.

Not paying much attention to Dipper's demeanor, Bill practically launched himself into his bed face first before rolling over onto his back so he could glance up at Dipper. "Don't like quidditch, or don't like that you're not good at it?" Bill countered.

Dipper immediately glared at the blond. "Shut up. There's nothing wrong with me not being good at quidditch."

Bill began throwing his pillow in the air, casually playing a one person game of catch as if he did not realize the brunette's want to curse him. "Is that what Red told you after your miserable attempt to impress her by inviting her to tryouts last year?"

Dipper's hand twitched for his wand. Impulsive was more of a Mabel trait, but Merlin, he would be lying if his first instinct was not to send a bat bogey hex Bill's way. The Ravenclaw did not bother to speak instead just silently frowning.

Bill sat up after catching his pillow for the upteempth time. "Sit down, Pine Tree." Bill patted a spot on his bed. Dipper tensed up. "I just saved you from Pyronica. I'm not going to do anything to you." Dipper looked at Bill with distrust as if waiting for more. "Yet." And there it was. Bill chuckled. "Plus you look like you don't know what to do with yourself. Relax. You're in the dorms. Not some old fashioned pureblood social gathering."

Hesitantly, Dipper sat beside Bill on the bed. He lightly pulled and pinched the sheets, keeping his hands busy and trying to direct his focus on something other than the Slytherin. The brunette was quiet for a moment before breaking the short lived silence. "Now what? Don't tell me we're actually going to study."

Bill shrugged. "We could. We also still have to work out your end of our deal."

Dipper froze at the reminder. He basically handed himself over to Bill on a silver platter by proposing a deal. Once more, Bill did not seem to notice Dipper's on edge demeanor. Or just did not care. Dipper was willing to bet on the latter.

"Pyronica's probably already blabbed about us," Bill mentioned, switching the subject. "Likely knows our excuse was a load of dragon's dung too." He chuckled and began to play with Dipper's hair. "Don't be surprised if people think we're sleeping together."

Dipper's face suddenly matched a the scarlet of a Gryffindor banner. "But I- They can't- We're not-" he stuttered, unable to piece together a coherent sentence.

Bill cut him off, teasingly singing, "Think before you speak, Pine Tree~"

Dipper huffed. Just great. After years of mostly flying under the radar, this was exactly what he needed. He frowned as Bill twirled his fingers in his curls. "Stop playing with my hair." He crossed his arms over his chest, moving back a bit to create some space between him and the blond.

"But it's fluffy." Bill pouted, pretending to be deeply upset. "It's the least you could do after I helped you."

Dipper sent Bill a deadpan glare. "You're going to hold that over my head for as long as you can, aren't you?"

Bill grinned. "Got that right." He leaned in towards Dipper and ruffled his hair. "See? You're catching on."

Dipper pushed Bill's hands away, muttering a mere "stop that."

Bill leaned back into his earlier spot. "So about that deal.. How about for the official terms, you're at my beck and call for the rest of the year?"

"No way," Dipper immediately objected. "I'm not agreeing to that."

Bill rolled his eyes. "There's nothing for you to agree to, kid. Either this or I turn you into a snake like Pyronica was going to." Dipper glared at Bill but otherwise was silent. "You know what. Just turning you into a snake seemed a bit too tame, especially for her. Maybe I'll make you a flobberworm." Bill shook his head, still not pleased. "An actual pine tree? Nah. How about a lamb-"

Dipper spoke up before Bill could go on any further. "Okay. Okay. You have a deal. I'll do it." He huffed. "Just at least give me enough time to do school work. I can't get behind on my studies during my O.W.L.s year.."

A large grin appeared on Bill's face. "Of course, Pine Tree. We can't have you flunking. Goes against the whole me tutoring you thing." Dipper did not bother to remind the blond once more that the tutoring claim was a lie. "Deal?" Bill held his hand out, ready for a handshake.

Dipper bit his lip, tensing up once more. His gaze anxiously flickered from Bill's face to the Slytherin's hand. With a swift nod, he shook Bill's hand before more regret could fill him. "Deal."