Santana was the first one to notice that there was something off about Brittany, which wasn't surprising considering the fact that the rest of the Gleeks always shrugged off whatever she said or did as a result of her sub-par cognitive processing skills. But Brittany had been unusually quiet for the last week or so, and she wasn't eating at mealtimes. Which, normally, wouldn't be odd, but she was even grimacing and refusing to drink the Sue Sylvester Master Cleanse when Santana offered it to her. Also, the light shadows beneath her eyes that nobody noticed were getting darker, her bones standing out a little more, and Santana caught on to the fact that the guys (and girls) in the hallways in between classes no longer checked Brittany out as she passed by. It wasn't that she'd become unattractive (Lord knows, she hadn't), but she was definitely less healthy, and Santana was starting to get weird vibes from her. Like maybe she was brooding over something bad that had happened between them, which just wasn't possible because Brittany was like a goldfish – she couldn't remember what she had for breakfast, let alone if they'd fought.

But it wasn't until Wednesday that Santana realized that there was something really, truly wrong.

On Wednesday, right after classes ended, Santana walked up to Brittany as she was coming out of her Art History class (the only one they didn't have together), and she must have surprised the air-headed blonde, because when she slipped up next to her and grabbed her hand like good BFFs always did, it only took a nanosecond for Brittany to whip around and slap Santana across the face with the back of her hand. And despite the shock of the sudden violence and the noise from the other kids filling the corridor, Santana was almost positive that she'd heard Brittany snarl. But when she regained her composure and straightened up, rubbing her cheek as it began to turn red, Brittany had vanished.

Too confused to do anything else, Santana reset her steely expression, and briskly strode to the choir room for Glee practice. The other Gleeks milling around as they waited for Schuester to show up looked surprised when she walked in without her sidekick, but she held her chin high and sat in her usual seat at the back of the class. Kurt and Mercedes watched her, one-quarter concerned and three-quarters hoping for juicy gossip, and she repressed the impulse to stomp over to them and punch both of them in the face. Not punching the Gay Boy became even harder when he plopped into the seat right below her and leaned forward, his eyes wide and eager as he said, "Did you and Brittany have a fight?"

"No," she snapped. Which, technically, was true. It hadn't really been a fight. She had no idea what she'd done to provoke Brittany's anger, because frankly she'd never seen Brittany angry before. Maybe Brittany had thought she was someone else? Maybe she had thought someone else was Brittany? Kurt was about to ask something else, but she flashed him a look that made him gulp and return hastily to his seat beside Mercedes, murmuring that approaching her had been a bad idea. Damn right.

Brittany finally walked in five minutes later, looking ill. Santana looked up hopefully, waiting for her friend to take the chair next to her, but Brittany didn't seem to notice that Santana was there, and she sat in the front. Her eyes were almost half-closed, like she hadn't slept in a couple of days, and her skin had a light green tint to it that made it look like she was about to throw up.

"You okay, Brittany?" Tina asked.

Brittany looked over at Tina as if she was surprised the other girl was there. "Huh?"

"Are you all right? You look sick."

"I'm fine."

Tina gave her a long look like she knew Brittany was lying, but resigned to go sit beside Artie, who narrowed his eyes at Santana as if she'd done something to the blonde, which really just pissed her off enough to break Artie's legs. Who cares, he wouldn't feel it anyway. But she didn't get up, too preoccupied with her counterpart's unusual behavior to do anything but sit and stare at Brittany's ponytail.

The club was halfway through the first ensemble number of the day when Brittany stopped moving. Like, legit stopped moving. She froze to the spot, her arms raised as she was about to clap as part of the dance number, her eyes sliding more out of focus than they usually were.

"Brittany?" Mr. Schuester said, wondering whether the girl's sudden lack of movement was actually something that needed to be worried about or whether she was just being…well, Brittany.

The other gleeks stopped dancing to see what was up, and Santana stepped in front of her, gripping her shoulders. "Britt, come on, talk to me," she said, knowing in the back of her mind that right now she looked completely and utterly freaked out. Her pride be damned, though, this was bad. Very bad. "Brittany," she said again, louder, cupping her friend's face in her hands.

Mr. Schuester walked over, and Santana was briefly aware that the rest of the Gleeks were backing away as they sensed that this was not something they wanted to be close to. Cowards. They didn't care about Brittany, they only cared about themselves. But Santana cared. "She's burning up," she said to no one in particular, and Schuester immediately assumed his stoic teacher face and ordered that Finn run and get the nurse.

"We don't have a nurse," Finn said, his eyes wide as he stared at the statue-ized cheerleader.

Mr. Schuester swore under his breath as he remembered that Figgins had yet to hire a replacement. He was about to tell them to call 911, but then Brittany's head jerked back and she fell to the ground, her limbs dancing as she convulsed. Santana shrieked and dropped down, trying to hold her friend in place, and Schuester whipped out his cell and dialed 911 himself. Then, things started to get weird. Brittany's eyes rolled back so nothing was visible but the whites, her jaw opening and closing while her lips stayed clamped shut – she looked like she was trying to swallow her tongue and vomit at the same time. Her body went rigid, the tendons in her neck standing out and her fingers twitching like dying spiders.

And just as suddenly as she'd started, Brittany stopped moving again. It wasn't like the time before, where it had been like someone had just pressed a pause button that only affected her and no one else, but it was somehow just as frightening. She was lying on her back, breathing hard, her eyes wide and staring at the ceiling. Santana was saying her name over and over again, trying to gain a response and completely ignoring the other Gleeks' reactions as she desperately shook her best friend's shoulders. Even more terrifying than her lack of movement, however, was that her pupils had completely blown, covering up her blue irises entirely and turning her eyes black.

The entire club fell silent when Brittany opened her mouth and spoke in a foreign language, her voice unnaturally flat and her eyes vacant. Santana barely heard Artie's sharp intake of breath, as if the half-bastard actually understood what she was saying. Then, abruptly, Brittany rolled over and emptied her stomach onto the floor.

"San?" she said. Her voice sounded so small and afraid, her hands were shaking, and she was on the verge of tears. "I don't f-feel good."

Santana didn't know what to say, so she drew Brittany into her arms and held her as tightly as she dared. "It's going to be okay, Britt."

The quiet squeak of wheels on linoleum made Santana look up to see Artie stop directly in front of them. "What do you want, Wheels?" she snapped.

He ignored her. "Brittany, do you remember what just happened?" he asked gently.

Brittany sniffled and shook her head. "I'm scared."

"I know," he said. Santana glared at him. Comforting Brittany was her job. He didn't even know her. "But I have something for you. To protect you."

Brittany looked up hopefully as he pulled something from around his neck. It was a golden cross on a chain – everyone in Lima knew the Abrams were Catholic – and he dangled it in front of Brittany's face, waiting for her to take it. He was the only one in the room who didn't look surprised when she recoiled instead, her lip curling and her pupils swelling again.

"Brittany?" Santana said. This was getting way too weird.

Brittany didn't take her eyes off the cross hanging from Artie's hand, and a low, threatening growl began to float from between her clenched teeth.

"Artie, what are you doing?" Mr. Schuester said, watching the exchange with wary eyes.

Artie shoved the necklace into his pocket and out of Brittany's sight. "Mr. Schue, you need to get the others out of here," he said, a small trace of fear lacing his words.

"What are you talking about?"

"I know what to do."

"Artie, you are not a medical professional," Mr. Schuester said sternly. "The best we can do is wait for the ambulance to get here."

"Trust me, Mr. Schue, this isn't a medical problem."

All eyes landed on Artie, shocked by the urgent authoritative tone in his voice. Brittany was still growling and Santana was starting to get really freaked out. So freaked out, in fact, that she decided to stop wasting her energy on her normally stony composure and looked to Artie; the guy did seem to know what he was talking about. "Abrams," she said. "You know what this is?"

He nodded. "Everyone should leave," he repeated, looking pointedly at the others. "I'm not kidding, guys. This is dangerous."

"We're not going anywhere," Mercedes said, crossing her arms. "She's our friend, we're not leaving her to the dogs."

Artie almost looked angry with her for talking back to him, but he apparently thought it would take too much precious time to argue with her, because he shook his head and said, "Your funeral."

Brittany pulled herself to her feet, her shoulders hunched, glaring at Artie with a sort of predatory delight in her blackened eyes. "You want to play with me, boy?" she hissed. Her voice sounded like it was coming from somewhere deeper than her throat.

"You've got no business here," Artie said, and the others flinched at the seriousness in his tone. A muttered "Holy shit" from Puck went unnoticed.

Brittany's mouth stretched and she began to laugh, a slow, menacing cackle that made Santana jump back, both in fear for Brittany and in fear of Brittany.

The laughing grew louder. "Trick or treat, you've got no priest!" Brittany taunted.

"Guys," Artie warned without moving his gaze away from Brittany. "Get. Out."

A screeching howl ripped from Brittany's throat, and she leaped at Artie, her hands colliding with his chest and tipping his chair back. They landed on the floor hard, Artie's head smacking the linoleum as Brittany pinned him down, and Tina shrieked his name. Artie couldn't respond, however, as he was busy trying to keep Brittany's hands away from his neck. She was snarling and spitting in his face, which would have been scary enough had her eyes looked normal. Mr. Schuester, who up until then had been unable to do anything but watch in horror with the rest of them, finally sprung into action and wrapped his arms around Brittany's torso, trying to pull her off of Artie. "No, don't—!" Artie tried to warn him.

As soon as the teacher touched her, Brittany twisted around and latched her hands around his throat, seeming to forget about Artie completely. Schuester tried to let out a yell of surprise, but all that came out was a strangled gulp as his mouth opened like a fish's, trying to suck in air. His hands wrapped around her wrists, trying to push her away, but her hold was superhumanly strong and she just growled loudly in response to his struggle.

Artie rolled over and leaped to his feet, shouting at the group, "Someone get Coach Sylvester!"

The rest of the gleeks, however, were more concerned with the fact that Artie had just stood up on his own, with no evidence of him ever even needing a wheelchair in the first place. "What the hell—!" Finn started as the rest gaped.

"Just do it!" Artie yelled, turning back to where Brittany was choking the life out of his Spanish teacher. No time to explain his sudden ability to walk. Kurt and Mercedes streaked out of the room to look for the cheerleading coach, and Artie grabbed his crucifix from the floor where it had fallen out of his pocket after Brittany tackled him, and pressed it to the side of her neck. Immediately, she let go of Schuester's neck, letting him drop to the ground spluttering and coughing, and released an unearthly scream that sent tidal waves of goose bumps over the gleeks' skins and raised the hairs on their necks. She fell to the ground, thrashing like a spider on a hot stove as she ripped the cross away from her skin.

"Artie…" Schuester coughed. "What is going on?"

The formerly handicapped boy glanced at the clock, agitated. "We have eight minutes before the ambulance gets here. Puck, Mike. Hold her down."

They didn't respond at first, both still shocked by the terrifying sight of the sweetest Cheerio at the school attempt murder, but also unused to the thought of Artie giving orders.

"Do what he says." Sue Sylvester strode in through the doorway, scowling at Brittany like she'd gained ten pounds the day before Nationals, Kurt and Mercedes trailing behind her. When the two boys still didn't move, she glared at them and shouted, "Now!"

At Sue's command, Puck and Mike snapped into reality and rushed over to where Brittany was curling and uncurling like an insect under the glare of a magnifying glass, her eyes rolling in circles. She was emitting an unsettling, gravelly noise that sounded part sick, part growl, part moan, her trachea moving up and down beneath her skin as if she was trying to swallow. Directed by Sue, they grabbed her by her shoulders, pulling her into a kneeling position. She was breathing rapidly, her chest shuddering beneath her Cheerio uniform.

Puck's eyes were wide enough to rival Miss Pillsbury's. "What the hell is wrong with her?" he asked, holding her at an arm's length. It was clear that he wanted to be nowhere within her reach after seeing her nearly break Schuester's neck.

"Demon possession," Sue answered, like demon possession was something that happened every day. "Abrams, where's that cross of yours? Never mind, you're never prepared. I brought my own." Out of her own pocket, she pulled out her own crucifix, about the size of her palm. Brittany thrashed against the jocks' hold when she saw what Sue was holding, growling louder. "Yeah, you love a challenge, don't you," Sue snapped at her, almost nonchalantly as she drew closer, the crucifix held threateningly in her fist.

Brittany roared something in the foreign language she'd called upon earlier, a tongue that sounded ancient and terrifyingly powerful. The lights in the room flickered, and Santana rushed into the meager protection of the rest of the group, all of whom were beginning to draw closer together.

"What language was that?" Mike asked, gulping, his voice unusually high.

"Aramaic," Sue said. "Language of Christ's disciples. It was just asserting its dominance over Brittany here." She turned her attention back to Brittany's demonic eyes. "And I can assure you that she most certainly does not belong to you. Brittany is a vital member of my Cheerio team, and I will not allow a lowly fallen angel like yourself to take Nationals away from me. Release her immediately."

"Adegere meum," Brittany hissed.

"Oh, Latin too, huh? Aren't you just full of tricks?"

"Trick or treat, you've got no priest!" the blonde girl cackled again, flashing an alarming grin.

"I'll have you know I'm a licensed minister of the Roman Catholic Church in forty-nine states, plus Puerto Rico. You have ten seconds to vacate my Cheerio."

"Adegere meum!"

"Are you just gonna repeat yourself all night?" Sue challenged. "Abrams, get me your Bible."

Artie nodded curtly and pulled the book out of one of the pockets on the back of his wheelchair and gave it to her. Bible in hand (which looked weird on so many levels regarding Sue Sylvester), Sue raised the crucifix and traced an imaginary cross in the air in front of Brittany, who let out a strange and unnerving harsh barking sound in reply. "In nomine Patri, et Filii, et Spiritus Sancti," she said, launching into a long intonation spoken entirely in Latin.

As Sue spoke, Brittany leaned backwards, bending at the waist. She stretched her mouth as wide as it would go and released another screeching howl that made most of the girls in the room clamp their hands over their ears as the lights shuttered on and off. A violent gust of wind suddenly whirled through the room, blowing the doors open and whipping at the gleeks' clothes and hair. Rachel and Kurt screamed.

"Abrams!" barked Sue when the Latin was done. She didn't have give him more instruction than that, though; he seemed to know what she wanted. He knelt in front of Brittany, placing his palms over her ears and his thumbs on her temples. Her tongue flicked out at him and she hissed, but he didn't so much as flinch.

"Veteris anguis," Artie said, holding her head firmly as she tried to pull away. "Discedere ex hic ministri de Deus, tuus domini."

Her lips pulled back in a grin, and she leaned close to his face, her black eyes coming far too close for comfort. "Ah, sed non is domini de meum, pueri," she teased.

"What'd she say?" Puck ventured.

Artie didn't break eye contact. "It just said that it doesn't answer to God."

"Well, no shit, Sherlock," Sue said from behind him. "It's a demon, it answers to the Devil."

Artie restrained himself from giving her a murderous look.

"Ashes and ashes, you all fall down!" Brittany bellowed, lurching backwards suddenly enough to break Artie's grip on her. "Trick or treat, I give you treats and tricks!"

"She's almost there," Sue said. "Hold fast, men."

Puck and Mike seemed to realize that Sue was addressing them, and they tightened their grip on Brittany's arms. Brittany, however, didn't like that at all, and she leaped to her feet, lunging at Puck's neck with teeth bared. "Shit!" Puck yelled as he jumped back, her teeth barely nipping his skin. It was enough to make his drop his hold on her, though, and with one side free, Brittany twisted around and somehow jumped onto Mike's back, her free arm wrapping around his neck and her teeth sinking into the skin just below his jaw. Mike yelped in surprise and fell down, Artie grabbing Brittany by the shoulders and trying with all his might to unlatch her from Asian Number Two. After a momentary lapse of shock, Puck came over to help, and together with their combined strength they were able to separate the two. Mike lay on the floor, breathing hard and clutching his neck where he was bleeding, red seeping out from between his fingers. Puck tore off one of his sleeves and pressed it to the wound while Brittany staggered in the middle of the floor, unbound. Her arms swung and clawed at nothing and her movements were stiff and jerking like a puppet's. She hissed and panted and spat, her blood-stained teeth clicking.

"How long until this thing is over?" Puck yelled from where he knelt beside Mike, nearly hysterical.

"Didn't anybody ever tell you that patience is a virtue, Puckerman?" Sue asked him. "It's over when it's over."

"We've only got two minutes until 911 dispatch is here," Artie said anxiously.

"Don't rush it, Abrams," she ordered. After a few more seconds of Brittany acting like she should be in a padded cell, Sue marched forward, and in one swift movement spun her around and pressed the crucifix to her chest.

The scream that followed resulted in two of the lights blowing out, leaving the rest to sputter and then turn off. The gleeks all shrieked and covered their ears as the screeching howl lasted for much longer than before, only growing louder as the seconds ticked by. Just as the kids were beginning to wonder how much air she was able to hold in her lungs, Brittany's head jerked back and she fell unconscious to the floor, twitching slightly. The lights that hadn't exploded flickered back on, and the wind was gone without so much as a whisper.

All was silent for a few moments until Finn spoke in a hushed tone. "Is…is it gone?"

Sue narrowed her eyes at Brittany's crumpled form, then knelt and took her pulse. "Get over here, Abrams," she demanded.

Artie lifted Brittany's eyelids, checking to make sure they had returned to their original color. "Pupils are dilated," he said.

"And her pulse is normal," Sue finished. "Would you look at that, we successfully exorcised a demon. Good teamwork, Abrams. Puckerman. Asian."

"It's gone?" Kurt echoed Finn's previous question.

Sue stood back up, brushing off her hands. "If by gone you mean banished to Hell until the next time it can find a way out, because Lord knows they always do, then yes, it's gone."

"Will it come after Brittany again?" Mercedes asked, her voice trembling.

"Demons never seek out my Cheerios twice, Mercedes."

After the ambulance arrived and Brittany was loaded into the back along with a hastily-created story about her suddenly having a seizure of an unknown cause in the middle of practice, Tina cornered Artie at the front of the school. She was fuming, and he wouldn't have been surprised if steam was coming out of her ears.

"Arthur John Abrams," she said, each word sounding like a separate sentence. "You owe me a huge explanation."

A/N: Never, never watch Glee and The Exorcism Of Emily Rose in the same day. Or this is what will happen to you. Gah, I feel so lame for writing this. Oh well. Was originally meant to be a oneshot, will end up as a twoshot. Sorry for my terrible Latin - there are frustratingly few online translators for dead languages. Endless thanks to JustRelax for letting me bounce ideas off of her forehead. Please leave a review, and check out my other Glee stories. Especially Shattered and Grasping For Ashes.