As the class shuffled into the room it soon became apparent that today's lesson wouldn't be like they were used to. After checking that everyone was present Professor Lupin told everyone to put their books aside, and then led the class out into the hallway and to the staff room without explaining why.

Dipper wasn't nervous per say, but he was frustratingly curious as to what they were doing in the staff room. It didn't help that his sister was tugging on his arm excitedly trying, and failing, to whisper her high-pitched thoughts to him.

"Why the staff room though? Do you think that the professors are secretly hiding a yeti in there?"

"It's not cold enough for a yeti in here Mabel." Dipper sighed, pointedly ignoring the amused looks classmates were sending them.

"Yeah but magic" She waved her hands to emphasize her point.

"Mabel, quiet." Dipper hissed. "The class is starting."

The staff room was devoid of anyone bar Professor Snape, who seemed less than pleased to see them all. After exchanging what could hardly be called pleasantries with Professor Lupin, Professor Snape left with his robe billowing dramatically behind him.

"How does he do that with his robe?" Mabel managed to whisper loud enough so the whole class heard her. A few members of class quietly laughed under there breaths at her words, but their attention was soon directed toward Professor Lupin who was now standing in front of a large wardrobe in the room. The wardrobe gave a sudden wobble, banging off the wall.

"Nothing to worry about," said Professor Lupin calmly because a few people had jumped backward in alarm. "There's a boggart in there."

Most people seemed to feel that this was something to worry about. Mabel looked at Dipper, having no idea what a boggart was, and saw his jaw was tensed and he was staring intensely at the wardrobe. She glanced at it too, wondering whether it would be like anything the two of them had faced before.

"Boggarts like dark, enclosed spaces," said Professor Lupin. "Wardrobes, the gap beneath beds, the cupboards under sinks — I've even met one that had lodged itself in a grandfather clock. This one moved in yesterday afternoon, and I asked the headmaster if the staff would leave it to give my third years some practice. "So, the first question we must ask ourselves is, what is a boggart?"

Unsurprisingly, Hermione was the one to answer. "It's a shape-shifter," she said. "It can take the shape of whatever it thinks will frighten us most."

"Couldn't have put it better myself," said Professor Lupin, and Hermione glowed.

At this point Mabel began to tune out her professor's words and looked nervously at her twin. "Dipper?" She tried to sound cheerful, wanting to alleviate the tension they could both feel. "I promise I won't tell anyone at home that your boggart turned into your lamby outfit."

Dippers lips twitched into an almost smile as he turned to look at her. "And I won't say anything when it turns into clay animation figurine."

She narrowed her eyes playfully at him. "Hey," she jabbed a finger at his chest, "we both know that they are things to be afraid of."

Dipper gave a small laugh. "Of course Mabel, it just seems funny without context."

Mabel stuck her tongue out at him but turned back to face the professor as they both caught the last bit of his words.

"…What you need to do is force it to assume a shape that you find amusing. We will practice the charm without wands first. After me, please . . . riddikulus!"

"Riddikulus!" The class repeated back.

"Good," said Professor Lupin. "Very good. But that was the easy part, I'm afraid. You see, the word alone is not enough. And this is where you come in, Neville."

Dipper watched attentively as Neville walked forward, visibly trembling.

"Right, Neville," said Professor Lupin. "First things first: what would you say is the thing that frightens you most in the world?"

Neville's lips moved, but no noise came out.

"Didn't catch that, Neville, sorry," said Professor Lupin cheerfully.

Neville looked around rather pitifully, though Dipper was thankful it wasn't him in Neville's place, then whispered, "Professor Snape."

Nearly everyone laughed. Even Neville grinned apologetically. Professor Lupin, however, looked thoughtful.

After a short discussion about Neville's grandmothers fashion choices Lupin instructed Neville to concentrate on them when he faced the boggart, thus creating an amusing image of the Potions Master.

"If Neville is successful, the boggart is likely to shift his attention to each of us in turn," said Professor Lupin. "I would like all of you to take a moment now to think of the thing that scares you most, and imagine how you might force it to look comical..."

Dipper felt his mouth go dry at the words. How was he supposed to make any of his fears amusing? After their summer vacation night terrors were no stranger to either twin, and Dipper couldn't find anything amusing about them. He tried to focus on one of the many things that appeared in his nightmares, but there were many to choose from. Pointedly he refused to think of anything that even resembled the worst of the lot; he had refused to even acknowledge passing thoughts of him since the summer, having tried hard to block that portion of the summer from his head.

Mabel was having the same issue. At first, she thought of Dippers suggestion -clay animation figures- but while she was afraid of them she knew that they weren't the thing she feared most. Unwanted, her head began to fill with different images and concepts; Dipper and her arguing over an apprentice with Ford; being trapped in a bubble of her own design and almost abandoning her brother for it; Grunkle Stan forgetting them; they all went through her mind in rapid succession before she could really process any of them.

"Everyone ready?" said Professor Lupin.

No, the Pines Twins both thought, as they felt their stomachs fill with dread.

Dipper silently wondered if they stuck to the back of the class would they get away without facing it.

"On the count of three, Neville," said Professor Lupin, who was pointing his own wand at the handle of the wardrobe. "One — two — three — now!"

A jet of sparks shot from the end of Professor Lupin's wand and hit the doorknob. The wardrobe burst open. Hook-nosed and menacing, Professor Snape stepped out, his eyes flashing at Neville.

Neville backed away, his wand up, mouthing wordlessly. Snape was bearing down upon him, reaching inside his robes.

"R — r — riddikulus!" squeaked Neville.

There was a noise like a whip crack. Snape stumbled; he was wearing a long, lace-trimmed dress and a towering hat topped with a moth-eaten vulture, and he was swinging a huge crimson handbag.

There was a roar of laughter; the boggart paused, confused, and Professor Lupin shouted, "Parvati! Forward!" Parvati walked forward, her face set. Snape rounded on her. There was another crack, and where he had stood was a bloodstained, bandaged mummy; its sightless face was turned to Parvati and it began to walk toward her very slowly, dragging its feet, its stiff arms rising —

"Riddikulus!" cried Parvati.

A bandage unraveled at the mummy's feet; it became entangled, fell face forward, and its head rolled off.

Mabel let out a shriek of laughter and tugged on Dippers arm as she remembered an incident where Dipper had sworn he'd seen a mummy. Judging by the pink tinge to his cheeks he knew what she was laughing at, which set her off again.

"Seamus!" roared Professor Lupin.

And so it went, with student after student being called upon to the boggart. Each new result of the spell earning laughs from various members of the class, though Mabel's was quite possibly the loudest.

"It's confused!" shouted Lupin. "We're getting there! Dean!"

Dipper was beginning to feel a bit calmer as he joined in the laughter, but his body was still tense. He was painfully aware that everyone's fears seemed to be basic subjects, nothing conceptual or as dark as his tended to be.

While he was unsure whether it was possible he was determined to avoid facing the boggart, and if that failed he was going to focus on one of his easier fears and hope that in its weakened state it would pray on that. With a straightforward strategy in his head he felt at the most ease since he had entered the room.

With a glance at Mabel he knew that she now wanted to have a go, the tell-tale shine to her eyes was reminiscent of the time she first grabbed her grappling hook. She was practically vibrating next to him as she watched the scene in front of them intently, mumbling something under her breath which he vaguely made out to be "clay animation" repeated over and over.

"Excellent! Ron, you next!" Ron leapt forward. Crack! Quite a few people screamed. A giant spider, six feet tall and covered in hair, was advancing on Ron, clicking its pincers menacingly. For a moment, Harry thought Ron had frozen. Then —

"Riddikulus!" bellowed Ron, and the spider's legs vanished; it rolled over and over; Lavender Brown squealed and ran out of its way and it came to a halt at Mabel's (who in her excitement had unknowingly pushed in front of Harry, dragging her twin behind her) feet.

The legless spider seemed to pause for a moment in front of the grinning girl, as if trying to decide what form to take.

Crack! It turned into a clay figurine of a Cyclops.

Mabel's grin faltered only a second before she rose her wand confidently. As her mouth formed the words of the spell though, the room filled with another Crack!

It had turned into a walkie talkie. In her confusion she lowered her wand, trying to figure out why the boggart would turn into that.

She jolted in shock when she heard the voice of her brother coming out of the speaker.

"I'll do it! I'll stay here and become your apprentice Great Uncle Ford!"

Mabel reminded herself that it wasn't true, her brother was standing right behind her. As she began to raise her wand again she vaguely wondered why it was reminding her of this event when it wasn't even the worst.

Crack!

Dipper was standing in front of her giving her a look she could only describe as pure apathy.

"Mabel." The boggart said, in a voice that didn't belong to it. "I need to think about myself." It spoke as if it were explaining a simple concept to a child. A way that Dipper often spoke when he was trying to explain something from the journal to her. It was eerie how similar it was to the real Dipper.

"I'm not going to follow you around for the rest of our lives, and if that upsets you then too bad. I don't need you anymore."

Mabel began to tremble, her eyes beginning to tear up. She forced herself to remember that it wasn't real. Her real brother was standing behind her, and had -unbeknownst to her- gone to stand in front of her before professor Lupin had put a hand on his shoulder and informed him quietly that he would step in if she didn't defeat it within the minute.

She closed her eyes for a second as she tried to remember her dorky twin who she had shared so many adventures with. Focusing on the memory of their thirteenth birthday she began to calm down.

She raised her arm and confidently shouted "Riddikulus!"

The boggart, still in the form of Dipper, was now clad in nothing but a towel and was singing into a hairbrush. "Disco girl, coming through! That girl is you!"

Mabel gave a shriek of laughter, which grew even louder at the real Dipper's embarrassed shout of her name. Majority of the class joined in laughing as she turned around to give her brother a big, hug. Of course, in her excitement she underestimated her strength, sending the two spinning for a moment.

"Mystery twins for life?" She asked, knowing he wouldn't really be mad about the singing boggart.

"Mystery twins for life." Dipper confirmed with a wry grin.

As the two of them hugged both were silently hoping that they would never fell apart like their great uncles did in the past. While the two uncles had made up, there was still an awkward tension that arose from time to time.

"Well done Mabel." Lupin quietly congratulated from behind the twins. He opened his mouth to say something else when suddenly the boggart shifted again.

The twins had shifted when they hugged, and so now Dipper was in front of her and, more importantly, the boggart.

The loud Crack! Had made many students jolt in surprise, and even those that hadn't were surprised to see what it had turned into. To the rest of the room the boggart looked like an old man, nothing particularly odd about him.

To the twins he was family.

"Grunkle Stan?" The twins confusedly whispered in synch.

The boggart looked at Dipper in confusion.

"Uh…" The boggart spoke in the familiar croaky tone of their great uncle. "Who the hell are you?"

Dipper made a confused smile before he realized what was happening. Mabel had obviously figured it out too because she seemed to be tearing up again. The boggart was showing what could have happened to Stan, had he not miraculously gained his memories back through the help of them.

With a sad sigh Dipper raised his arm, thankful that Grunkle Stan's memories came back after battling Bill. His arm faltered as he thought of the demon's name. He hadn't meant to do that.

"Hey." 'Grunkle Stan' spoke directly to Dipper. "Why are you looking so weird."

Dipper licked his lips nervously, preparing himself to complete the spell.

"Are you afraid of me, Pine Tree?"

With an audible clatter Dipper dropped his wand in shock.

"Wha-Bu-Ho" He spluttered.

The boggart still looked like Grunkle Stan apart from his pupils. Dipper recognized them immediately, they were a sign of possession by Bill Cipher. His voice sounded similar to Stan's but had developed an echo similar to Bill's actual voice.

"Speechless Pine Tree?" The boggart grinned. "I'm not surprised."

Dipper trembled, overcome by fear and shock.

"Awwww." The boggarts voice began to change until it was clearly just Bill's voice. "You look so pitiful right now. That's no fun." It shook its head mockingly.

"You're not the real thing." Dipper's voice was audibly trembling. "We defeated you."

The boggart lifted its head back and gave an inhumane laugh that made the entire class break out in goose bumps. "Are you certain about that? What about you Shooting Star?"

Mabel froze under the golden stare, unable to say anything.

"Boy you Pines' have really gotten just," it sighed melodramatically, "sad."

Dipper glared at the boggart, his fear temporarily replaced with anger. "You're just a boggart, you're probably the weakest thing we have gone against yet." He forced his voice to stay calm. "And we did defeat him, he has no way of getting back."

The boggart glared back at Dipper for a moment, before its mouth stretched into a grin too large for their Grunkle's face. "You severely underestimate my abilities Pine Tree. The dreamscape has slowly been giving me power- the two of you have been helping me with that."

Both Mabel and Dipper shuddered at the implications of that.

"Besides" the boggart continued "this boggart is merely a convenient temporary vessel for me. As a dream demon who hides in your nightmares, you should have known better than to play around with a being who manifests fears. But I suppose I can thank your teacher for that." At this he turned around and grinned at Professor Lupin. "You unknowingly helped me out Wolfy, so thanks."

The professor, who had until then been watching the boggart exchange in curious confusion (as boggarts could only every exchange a few phrases normally. It would take an immense amount of fear for them to say any where near as much as this one was), gaped at the boggart in shock.

"Whelp, I think I might have given your pathetic teacher a bit of a fright." The boggart laughed. "Oh you meatbags are so amusing!"

Having been reminded that they were in a classroom Dipper reached down to pick his wand up again.

"DON'T LOOK AWAY WHEN I'M TALKING TO YOU PINE TREE"

Dipper stood up impulsively and was shocked to find the boggart standing a few inches away from him now, instead of the few feet he was before. His eyes flickered from the angry red they had just turned to, back to gold.

"Before you try to get rid of me with that sad excuse of a stick, I just wanted to say a few words." A grin that looked positively wolfish was on it's face. Before Dipper could take a step back the boggart grabbed one of his arms and observed the scars on it.

"Good times, huh?" It snickered as the boy tried to pry his arm away. It took a moment to poke one of the scars before taking a step back, dropping to boy's arm.

"Look at me Pine Tree." It's tone demanding. "I want you to remember that I'm never really gone. I always have a backup plan, I always come back, I will always find you, and you can never get rid of me."

It was at this moment that Dipper became aware that the boggart wasn't just standing in front of him. During the conversation it had moved around slightly, putting itself in front of other students as it remained speaking to him. It now stood diagonally in front of him, placing itself between both him, Mabel, and Lupin (who had stepped forward with his wand out).

Glancing lazily at the three of them the 'boggart' spoke. "Shows almost over now, but thanks to the power boost you Pines have just given me I'm sure I'll be seeing you both very soon."

Dipper felt his head go faint at his words.

"Aww shucks you two both look excited! I can't wait to come visit you Shooting Star, your selfish choices are always hilarious to abuse, and I can't forget Pine Tree's adorable screams of absolute terror. Ha! You guys have the best nightmares."

Dipper practically growled at the most-likely-demon-possessed-boggart. "We're not afraid of you Bill!"

Before anyone could comprehend it, it was grinning right in Dippers face.

"Oh, Pine Tree," It eyes flashed as it gripped his shoulders. "you haven't even begun to see what I can do."

Multiple class members yelled in shock as blue flames licked Dipper's shoulders, making him cry out in fear.

"Riddikulus!" Shouted Professor Lupin, at lose as to what else he could do.

The spell hit the target fully, and yet nothing seemed to happen for a moment.

Slowly it's hands slid off Dipper's shoulders and it turned around to face the professor.

"Woof."

With that single word most-likely-Bill's eyes rolled into the back of its head and collapsed to the ground for a moment before the loud Crack! filled the room again.

It was now a silvery-white orb hanging in the air in front of Lupin. Catching his breath, the professor raised his wand and tiredly cast "Riddikulus!" again.

The orb deflated like a balloon, floating through the room and earning startled shrieks of nervous laughter before it hid itself back in the wardrobe.

"Class dismissed."

After a few moments hesitation the class began to filter out, though a few tried to stay behind and look at the Pines Twins who hadn't moved.

"Class dismissed." Lupin looked pointedly at those ones until they left.

Looking at the twins, who seemed to be in shock, in concern he conjured up a comfy couch behind them in case they wanted to sit down. They didn't appear to notice it as Dipper crumpled to the floor trembling, his sister wrapping her arm around his shoulders.

"Oh-God-Oh-God-Oh-God-Oh-God-Oh-God." Dipper rocked back and forth. "This can't be re-I can'- I- No."

Tears were streaming down both of their faces.

Dipper felt his stomach convulse and leant to his side as he unintentionally vomited from the shock.

With a wave of his wand Lupin silently vanished it.

After a few moments of the twins sobbing together, and taking comfort in each other's presence Mabel took notice of the couch behind them and gently lead her brother to sit on it with her.

Turning to the professor she asked in a croaky voice "Do you think we could get some of those dreamless potion things?"

"Of course." Lupin spoke in a soft voice. "I'll send a request for them right away."

She nodded her thanks and continued rubbing her brothers back as he stared at a section of the wall, deep in thought.

After conjuring a patronus which was sent to Madame Pomfrey, Professor Lupin conjured some chocolate, which he then silently offered to Mabel. She took it silently and again nodded her thanks, breaking the piece in half for the two of them to share as he intended.

"There's more if you'd like," he spoke as softly as he could, "it should help you feel better. You can also stay in here as long as you like."

"Won't the teachers come in here?" Mabel's voice was quiet and coarse.

"I can conjure a message informing them to stay out of here." He informed. "As long as I'm in here 'supervising you' you could stay in here for the whole night and it would be fine."

"Thanks." Mabel sniffed and gave him a watery smile.

After conjuring a sign on the front door of the staff room, informing the members that the room wasn't to be entered, Professor Lupin sat down on one of the many chairs in the room and conjured himself a book, preparing himself to keep watch over the twins for as long as they needed it.

A/N: I couldn't get this idea out of my head so I had to write it out. Hopefully it hasn't been done like this before. Please be sure to review!