Author's Notes: This is the first fic submission for Operation: SeBlaine 100, a project whereby I attempt to write 100 SeBlaine one-shots by the end of August 2012. This one-shot is based on one of the more unusual prompts that I have received, and it is also a lot more challenging because of the specifications. And since it is Friday the 13th at where I am, it only makes sense to start it off with an AU story that features a bit of the supernatural. Please note that this is the first time that I write about this particular supernatural subject. The prompt detail is at the end of the fic. If you have any prompt ideas, please send them my way (the more vague and more simple, the easier it may be). Also, I have a Tumblr where I talk about all of my SeBlaine WIP, I'd be honored if you can follow me at "rykerstrom(.)tumblr(.).com". Big thanks to my betas for proofreading this. I hope you guys enjoy this~! Happy Friday the 13th!

ACONITUM

Blaine's limbs felt like lead. His mind was a little hazy from the orgasm, but he was keenly aware of Sebastian still moving inside of him, his pace fast and getting more erratic with each passing moment. Blaine wondered if it was normal to feel this sensitive afterwards. He could feel Sebastian's every stroke and every thrust, yet all Blaine could do was to lay still and feel, gasping whenever he felt a particularly hard thrust.

Sebastian went still and shuddered above him as his orgasm took hold. Blaine heard himself letting out a small whimper when Sebastian pulled out and laid down next to him. To say that he was feeling a bit sore was an understatement.

"Well," Sebastian turned on his side and pulled Blaine to him. "That, was absolutely amazing."

Blaine winced at the sudden movement.

"Are you okay there?" Sebastian actually looked concerned. "Was I too rough?"

"I'm okay," Blaine admitted and rested his head on Sebastian's shoulder. "I'm just not used to it."

"So, what brought this on?" Sebastian reached out and brushed away a stray curl from Blaine's forehead. "Not that I'm complaining but I sure didn't expect that."

"We're seeing each other, aren't we?" Blaine looked up, his gaze met by a pair of turquoise eyes. "I want to thank you for all that you've done for me. The aconitum, it worked."

"Wait." Sebastian sat up straight. "You mean the monkshood? It worked? How'd you know?"

"I ran into one of Cooper's flings this afternoon. I mean, the one that he infected." Blaine shuddered at the close call. "She was going to bite a kid, I panicked and kind of stabbed her with the syringe."

"And it worked?" Sebastian's eyes were wide with a mixture of disbelief and amazement.

"Her behavior changed right away." Blaine nodded and tried to get up slowly. "I think it's a cure. We can cure Cooper."

"That's ... that's great! It was just a theory, I'm glad it worked," Sebastian said as he tied off the condom and threw it into the rubbish bin. "Now we just need to get more monkshood, or aconitum, as you call it."

"I left them by the entrance when I came in."

"You're unbelievable." Sebastian leaned over to give Blaine a kiss. "You always think of everything."

"It's my brother we're talking about here," Blaine explained. "I can't take any chances."

"I know." Sebastian cleaned himself off quickly and pulled on his boxers and jeans. "Which is why I'm going to go downstairs and get started right away. You just stay here and relax."

Blaine reached for some tissues to wipe off the drying cum on himself before laying down on the bed again. There was now a cure. They could reverse Cooper's condition, and Cooper would never turn into a werewolf. Things could go back to the way they used to be. For the first time since Cooper had been attacked, Blaine felt a glimmer of hope.

A loud crash downstairs startled Blaine. It sounded too loud to be that of Sebastian dropping his supplies.

"Sebastian?" Blaine called out.

When there was no answer, Blaine hurried out of bed, pulling on his underwear and pants. When Blaine heard another crash and a cry of pain, he grabbed the closest shirt in sight and raced down the steps, ignoring the pain shooting up his spine. The commotion seemed to have come from the kitchen. As Blaine rushed into the kitchen, the sight that greeted him made him freeze.

Cooper was here. Cooper had somehow found them.

"Hi, little brother." Cooper's back was facing Blaine. "Hm, I can smell sex on you."

Cooper was standing over Sebastian, who was clutching his arm, his face twisted in an expression of pain.

"So, this is the guy that's fucking my little brother. What's his name again? Sebastian, right?"

"Coop …" Blaine ventured a step forward. "Don't do this."

"Don't do what? Oh, you mean kill Sebastian? Or do you mean don't hurt him? By the way, I might've broken his arm."

"Cooper, please." Blaine pleaded. "We found a cure for you."

"A cure? What makes you think I'd want a cure?" Cooper laughed. "Sure, I hated it at first, but this power that I feel now? I'm strong, I'm popular, people throw themselves at me. Why would I want to go back?"

"Cooper, you know that's not you." Blaine took another step forward. "You're not like one of them."

"One of them, Blaine?" Cooper spat. "The popular ones who are accepted for a change? Newsflash, Blainey. I'm done making stupid documentaries with you. I'm done being an outcast. I like what I am."

Cooper turned around. Blaine swallowed hard when he took a good look at his brother. The infection had progressed faster than he thought. Cooper's face now looked like a hybrid of a human and a wolf. His light blue eyes looked as though they had sunken into themselves. His nose and jaw had elongated and narrowed to resemble that of a snout. Blaine was quite certain that the only reason Cooper could get by without alarming anyone was due to the fact that it was Halloween tonight.

They had to do this fast, or else Cooper would really become a lycanthrope.

"Do you know what else is great about this?" Cooper lifted his hand to show Blaine. "Claws. Nobody will fuck with me anymore. It's so easy to kill."

Behind Cooper, Blaine could see Sebastian's horrified face.

"Blainey, I don't think I like your boyfriend." Cooper turned his attention to Sebastian again. "I don't like anyone fucking my baby brother. No one's allowed to take you away from me."

"No, Cooper! Don't!" In a panic, Blaine grabbed the closest knife he could find. "No, listen to me, Cooper. You haven't lost me."

"What're you gonna do with that knife, Blaine?" Cooper grinned. Blaine had to resist the urge to run away at the sight. His brother looked absolutely terrifying. "You gonna attack me with it?"

"No! I …" Blaine bit his lip. There really was no other choice. He pressed the tip of the blade against his palm, hissing in pain as he made a small cut. "Give me your hand, Cooper."

Behind Cooper, Blaine could see Sebastian shaking his head.

"Interesting." Cooper extended his hand anyway.

With his trembling hand, Blaine made a small cut on his brother's palm and pressed his own palm to Cooper's so that their blood mixed together.

"You're my brother," Blaine explained. "We're of the same blood. See? I'm not going to leave you. Now I'm infected too. We'll be together."

"Really?" Cooper looked surprised. "You'll turn into a werewolf, just to be with me?"

"Yes, yes I would." Out of the corner of his eye, Blaine saw Sebastian getting up. "I'd do anything. You know that, Coop."

"As much as I'd like to believe you, little bro," Cooper looked at the shirt that Blaine had haphazardly thrown on. "I'm afraid that Sebastian's gonna have to go. After all, I—"

The rest of Cooper's sentence was cut short when Sebastian hit him over the head with the fire extinguisher.

"Sebastian!"

"I had to." Sebastian said defensively. "He broke my arm, and he's probably gonna kill us both."

"A fire extinguisher? Really?" Blaine took a closer look at Cooper, at least his brother was breathing. "Where did that come from?"

"This is a kitchen one. I set the stove on fire sometimes."

"Wait, what?" Blaine shook his head. "Nevermind that. Are you okay?"

"My arm's broken. So no, I don't think I'm okay."

"I'm so sorry. I—" Maybe he shouldn't have gotten Sebastian involved in this, but Sebastian was the only person he knew who was knowledgeable enough in folklore and chemistry to help.

"Forget about it. Just tie your bother up in the basement." Sebastian suggested. "I need to make the antidote before he wakes up and I'm going to need your help, now that I only have one workable arm."

"Okay."

Time was of essence, Blaine realized. This would be their one and only chance to save Cooper, and failure was not an option.

Addendum: So the prompt for this fic was "write a scene that talks about werewolves from either your own creation or from any werewolf movies you've seen, make it SeBlaine (if there's sex that's even better), and bonus if there's a Cooper appearance". That's how this fic was born as it's partly inspired by "Ginger Snaps". It was quite challenging given the unusual prompt. Aconitum is another name for monkshood or wolfbane. I am still taking prompts for Operation: SeBlaine 100. Please send them my way! Also, to get more information on my other SeBlaine WIP, I'll be honored if you can follow me on Tumblr via "rykerstrom(.)tumblr(.)com", I spend quite a bit of time there. Thanks for reading!