Author's Note:
So this takes place is s7 when Cas was cray-cray and stuff. Yes, enjoy.
-Cas

"Yeah alright. We'll head over." Dean hung up the phone and tossed it on the bed.
"Who was that?" Sam asked, taking a swig out of his beer bottle.
"Garth. Says he's got a case for us. Let's go."
The two brothers finished packing up their belongings and left the now empty motel room to clamber into the car parked outside. A few hours later, they pulled up to a motel in a town called Youngstone. Dean spotted the rail-thin hunter almost instantly.
"Garth, talk to me." He called and Garth walked up to him.
"I dunno exactly what's happening, to be honest. Something here seems to be taking the physically and mentally ill and dumping them in the river. Some live, some don't, but other than some bruising they don't seem to be hurt."
"Well that seems confusing." Dean groaned as Sam walked up.
"Any idea what it is?"
"No clue. Why I called you guys."
"Alright, how about we go ask around the family members, girlfriends, boyfriends, spouses anything." Sam said. Garth nodded in agreement.
"We're ready when you are." He gestured to his suit and tie.
"'We'?" Dean asked skeptically, but Garth was already walking back to his room.
One quick change and a short drive later, the group of hunters pulled up to the latest victim's brother's driveway. They were about to walk up to the door when Dean noticed a certain grey sock that was accompanying Garth, complete with a baby sock suit and tie.
"Uh Garth?"
"Yeah?"
"Why do you have Mr. Fizzles?"
"Mr..." Sam started, but stopped when he saw the sock.
"Excuse me, is Agent Fizzles." Garth replied and strolled up the walk. Dean rubbed his forehead with a groan and followed Garth up the way. Sam rang the doorbell and a scrawny kid opened the door.
"H-hello?"
"Hello, friend!" 'Mr. Fizzles' said. The boy looked at the sock in confusion.
"I'm Agent Fizzles and these are my comrades. Can we come in?"
"You're Feds?" He asked in a hushed tone.
"Yeah we are." Sam interrupted before Mr. Fizzles could continue.
"Can you help us?"
"Help you from who?"
"The monsters. They know where we are. They know who we are. And I'm scared of them. Mr. Fizzles, can you help us?" Sam and Dean both looked at Garth, Sam in a "well can you?" way and Dean in a "you gotta be kidding me" way. 'Mr. Fizzles' nodded.
"Of course I will. Now what are these monsters?"
"They're looking for someone. I know they are. And they know he's damaged. That's why they're taking all the damaged people. And once they know it's not the person they have, they dump them in a ditch someplace."
"Do you know anything about them?" Mr. Fizzles asked. The boy thought for a moment.
"Ooze." He said.
"Sorry?" Dean asked, leaning closer to the kid.
"One of them leaked black ooze. I saw it on my brother when they found him."
"Leviathans?" Dean asked.
"Looking for a damaged person? That doesn't seem right."
Mr. Fizzles shook his head in agreement.
"Garth. Control your sock." Dean said angrily. Garth turned back to the boy in the doorway who was looking at Mr. Fizzles like he was the world's answer.
"Mr. Fizzles, what are they? What are Leviathans?" Garth and Mr. Fizzles turned to look at the Winchesters.
"We will turn to our experts for that." Mr. Fizzles said. Dean rolled his eyes and started explaining. Garth wandered off of the path. He glanced over across the street and saw a man standing silently there.
"Uh oh Mr. Fizzles. I don't think that's a good guy." Garth whispered. The man flickered and suddenly the words 'Give us your traitor' flashed across his mind.
"Woah dude!" Garth yelled and the words disappeared, along with the man. Sam and Dean rushed over to him. It took him a minute to realize he had fallen to the ground.
"What happened?" Sam asked.
"Did you see the monsters?" The boy called from a few feet away.
"Mr. Fizzles did you see the monsters and their message?"
"Yes." 'Mr. Fizzles' called out. Dean rolled his eyes. Mr. Fizzles was laying in the mud a few feet away, but that didn't seem to bother either Garth or the kid.
"He said 'Give us your traitor'." Garth said.
"The same message." The kid said, his voice trembling. Garth clambered up and swiped Mr. Fizzles from the ground. He swung his sock occupied arm around the boy comfortingly.
"Give us your traitor?" Sam repeated.
"The damaged traitor. Are they talking about Cas?" Dean asked in shock.
"Cas?" Garth asked. "Who's-"
"Long story." Sam cut him off and turned back to Dean.
"Should we go back to the hospital and find Cas?"
Sam started to answer when Dean's phone buzzed off in his pocket. He checked it and his face went pale.
"Oh god. It's Meg." He answered the phone with a cringe, closing his eyes. After a few seconds, his eyes flew open.
"Oh no, no, NO! That can't- what do you- HOW DID THAT HAPPEN?" Sam heard a buzz from the phone as a reply but Dean looked like he was about to throw the phone.
"Yeah well FIND HIM. We're gonna drive over, and if he isn't back in your care when we arrive, I will jam my blade so far down your throat that you'll piss it out tomorrow. Understood?" He hung up before she could reply and jammed the phone into his jacket pocket.
"Sammy, car, NOW."
"What happened?" Sam asked.
"I'll explain on the way. Hey, hey, hey, no." He put his hand on Garth's chest before the hunter and his sock could enter the car.
"What?"
"We need you to stay with the kid and find out as much as you can about this monster. Okay?"
"Sure." Garth stepped back and put his arm around the boy. They almost looked cute together, like a father with his son, but Dean was too distracted to appreciate it. He climbed in the car and drove off.
"So what happened?" Sam asked when they were a few miles out.
"It's Cas."
"Yeah, I kinda figured that, but what did he do?"
"He's gone. According to Meg, a doctor reported him 'driving away in an ambulance with another patient yelling about Rorys and bees' to put it in their terms."
"I have questions about almost all of what you just said, but most important is what other patient?"
"Dunno. Guess we'll find out."
They drove the rest of the way without much talking. When they pulled into the hospital, they saw one of the nurses waving them down from the side of the lot.
"Meg." Dean growled when they saw who she was. They pulled up next to her and rolled down a window.
"Hope you've got that blade ready."
"So no word?" Sam asked and Dean rubbed at his eyes. Meg shook her head.
"They've got a manhunt of sorts out for them, but if I know the other patient, if they don't wanna be found, they won't be found."
"Other patient?" Dean asked. Meg gave a little sigh.
"Yeah. Her name was Lily Rose, in for a lot of bad stuff. She's completely bonkers, nobody knows everything that's wrong with her."
"And now her and Cas and touring the countryside. Awesome." Dean said and let his head hit the headrest on the seat.
"Look, I gotta get back-"
"Yeah sure, thanks Meg." Sam said and rolled up the window. Meg turned and headed back towards the hospital.
"So, what do we do now?" Sam asked.
"I don't know. Hope that something good happens?"
"Come on Dean. We've gotta help Cas out here. He could be in trouble."
"Could be? Dude, he's roaming the streets with a complete maniac. Of course I want to help him, but how is that gonna happen? What can we do except wait?"
At that moment, Sam's cell went off. He gave Dean a questioning look and picked it up.
"Hello?"
"Hello? Hello hello? Is anybody- hang on a sec." A girl's voice shot through the phone in a grainy pitch.
"There!" She said triumphantly as she began to sound like a human being again.
"Who is this?" Sam asked angrily. He didn't have time for this kind of thing.
"Well, you're Sam right?"
"Says who?"
"Oh, right. Sorry. I'm Lily Rose. I can see you guys in your car. Who's sitting next to you? Is that his boyfriend? Is that your boyfriend, Beeboy?" Sam sat straight up in his seat and stared around him.
"Where are you?" He asked frantically.
"Who was it?" Dean asked suspiciously but Sam hushed him.
"I'm not sure. Beeboy SAYS that it's not his boyfriend, but I think it is. Why were you talking to Nurse Masters before? Are you guys cops?"
"Is Cas with you?"
"Cas? Wha-" Dean started but Sam shushed him again.
"Who, Beeboy? His name is Cas? Is your name Cas? Oh it IS Cas. Huh. Never knew that. Oh, that must be the shortened version of your name. That makes sense."
"Come back to the hospital now!" Sam yelled into the phone.
"That's a no-can-do. Too many Rorys."
"What are- never mind. At least send Cas back."
"I already said, no-can-do. I'm not letting him near the Rorys either."
"Well then, can we come to you?"
"That'd be great, except we have no idea where we are."
"Am I facing you?" Sam climbed out of the car with Dean following him, trying to pick up every word of the conversation.
"Nope. Turn ninety degrees."
"Now?" Sam turned again.
"Other way." Sam rolled his eyes and turned back, now facing a forested area.
"Yes! We're waving." He squinted into the trees and could just make out two spots of white and tan among the leaves.
"I see you! Oh my god, I see you. Stay right there, we're coming up."
"Okay. But I think I hear some- BEEBOY!"
"LILY!" Sam yelled and took off for the trees, Dean close behind. As they entered the woods, they could hear the shrieks and sounds of an attack more with their own ears than through Sam's phone. They burst into a clearing just long enough to see the tip of the trench coat disappear behind a bush. Sam picked up the phone again.
"Lily? Lily?!" He heard a crackle and looked down to see the phone laying in a pile of leaves on the ground. He picked it up dejectedly and shoved both phones in his empty pocket.
"Come on Dean, let's go!" He yelled and the two ran after where the trench coat had been. After a short time, they realized how useless their search was. Dispirited, they both returned to the car.
"Well at least we know they're still in town."
"And that they just got attacked." Dean muttered.
"What are 'Rorys'?" Sam asked thoughtfully, leaning against the car.
"What are whos?"
"Rorys. Lily said there were Rorys at the hospital."
"That could mean anything. I mean, the girl's insane. She could be talking about fruit bats for all we know."
"I dunno. She seemed convinced."
"Of course she's convinced. It's her own brain that's gone haywire. What we've gotta focus on now is finding her and Cas. It sounded pretty gruesome."
"Yeah, I guess so. But how DO we find them? Seems pretty clear that they're in control about who sees them."
"But not if one of them's injured. They couldn't have gone far. We should get back out there, start searching again."
"Why, Dean? The thing that attacked them could still be out there and we don't even know what it is. Come on, let's just get a motel room and call Garth, see if he's got anything."
Dean grudgingly agreed and the two got in the car and drove away to yet another crappy motel room. When they walked through the door, Dean collapsed on the bed and started snoring. Sam gave a little smile and sat down on a chair. He was feeling pretty wiped himself, but he knew he had to stay awake if Garth called with any information. A few hours of nothing passed and he could feel himself slowly nodding off when Dean's phone went off on the table next to him. Sam shot his head up and grabbed the phone.
"Garth!" He half yelled into the thing.
"Uh, no. I guess you're expecting a call?"
"Meg. Yeah, sorry."
"Want me to call back, or-"
"No, no it's fine. What did you need?"
"We just got a report that the ambulance Cas and Lily drove away in was found outside of the woods covered in black ooze and blood."
"Black ooze? Oh n- alright. Thanks Meg."
"That's not all."
"What else?"
"They found a blue, misty kind of substance hovering around the ceiling. Sound familiar to you?"
"Uh, no actually."
"Me neither. Well, keep me posted."
"Yeah. Thanks Meg." Sam hung up and sat back in his chair. He could still hear Dean snoring, but now he was getting restless. He HAD to do something. After a few more painful minutes, he couldn't wait any more. He scrawled out a note for Dean and left the room. Leaving the car in the lot, he practically ran back to the woods, this time to the place where they found the ambulance. There was still a swarm of people around it, Meg not included. Sam showed his badge to the cop by the police line and he let him through. One of the park rangers walked up to explain what they found but he waved him off and went right to the back of the truck. Sure enough, the entire back was a bloody, leviathan-ooze covered mess. He leaned forwards and scanned the top of the vehicle, but he didn't see any sort of mist. He pulled his head out disappointed when he heard a crack and a gasp, followed by a little groan coming from the woods. Sam looked around him. All of the officers still there were otherwise occupied. He turned to face the woods and crept forwards.