I do not own Supernatural.
Dean wondered what it meant that he was so tired he dreamt of sleeping. He knew he was dreaming now, curled in a warm bed at Bobby's, dreaming about being asleep in the same bed. He never should have let Sam talk him into watching Inception.
His dream doze was ended when he noticed the bed was warmer than usual. He felt movement on one side of him. Dean turned to see what it was and immediately scrambled backward, falling off of the bed. He hadn't expected to wake up with God.
Castiel whimpered on the bed and whispered Dean's name pathetically. Dean peered over the top of the bed. Something was wrong. Cass was sweating, his forehead shiny with it, and he seemed to have trouble keeping his eyes open. This was not the arrogant false deity Dean had been so scared of before. Dean took one look at him and knew that this creature on the bed was his angel, and he was hurting.
He climbed back on the bed, still hesitant to touch Cass. "What happened?" he whispered, unwilling to break the hush of the room.
Cass took a deep breath, and Dean noticed he was shaking.
"You were right. It was too strong, or I was too weak and now it's winning." He paused, panting for breath. "Help me, Dean."
"What's winning? Cass, what's going on? I knew you were slipping, but naming yourself God? And now you show up like this..." He trailed off as he realized that Cass was trying to speak.
"I have been prideful, but I could never be that prideful or blasphemous. My father is the Lord. The one, true God. But it doesn't think so. It thinks it deserves to be God. It's dangerous, Dean, but I can't hold it off. If it knew I had been to see you-" Dean reached out and put a hand on Cass' shoulder.
"Slow down." Cass nodded, shallow breaths slowing to a normal pace.
"Now start at the beginning." Cass' confused head tilt number four made an appearance and Dean felt his lips pulling into a grin.
"The beginning of time? I don't understand why that's relevant to our situation, Dean." He resisted the urge to smack his own forehead.
"Okay, tell me what happened in purgatory."
At this, Castiel seemed to droop even more. His eyes slid closed and he took a few deeper breaths.
"When I got there... The souls, it was intoxicating. I knew I had to harness the power and destroy Raphael. I hadn't anticipated that one of the souls might be stronger than me."
Dean's eyes shot wide as the truth dawned on him.
"It wasn't you. Your meatsuit's been hijacked?"
Cass nodded sleepily again.
"I am afraid something else is driving. I'm trying to hold it back, but it's harming me to do so."
Dean looked him over and had to do a double take. There was a large, wet bloodstain on Cass' white button-up. It looked like he'd pissed off a tiger.
"Holy crap, Cass!"
Dean reached down, unthinking, and pressed his hand to the wound in his stomach, instinct telling him to apply pressure to slow the bleeding.
Cass grunted in pain.
"I don't know how long I can do this, Dean… I'm tired… It's tearing me apart. It's so strong-"
"You're stronger, Cass! I've seen you in action. You're a badass, man! You can fight this!"
"Dean!" That wasn't Cass, it was Sam's voice, breaking through his sleep.
Dean jolted up in bed and stared at Sam for a moment, panting.
"We have to save Cass."