"He doesn't belong to you," Lucifer says from over Sam's shoulder. It's telling that Sam doesn't even flinch anymore. He glances down at his hand and sighs.
It doesn't matter if he talks to Lucifer or not. They're at a stalemate. Sam can't send him away. Lucifer can't kill him. The closest Sam has ever come to victory over the devil is compromise that keeps him close. But Lucifer sounds angry, now.
"What doesn't belong to me?" Sam asks. He's tired. He was feeling much better earlier, but there was the whole mess with the real life Wicked Witch. He feels like he might collapse. Maybe Dean's right. Maybe he really isn't ready to hunt. He keeps passing out, forgetting things… At least Dean keeps his head on straight, eyes on everything Sam misses.
"Shut up, Sam," Lucifer says, condescending to him with affection. "And you. Stop playing with my toys, little brother."
No one answers Lucifer. Sam, reluctantly, turns his head to face him. Lucifer's glaring a hole into his skull, like he wants to reach inside and pull things out chunk by chunk. The air in Sam's lungs comes out in a rush. Lucifer looks through him, as though Sam is the illusion. "Get. Out," he snaps.
Sam blinks and-
"He never said yes to you. He doesn't even know your-" Lucifer is enraged now, and Sam's sitting differently than he was a moment ago, and his mouth feels dry. Lucifer's gaze, sharp as ever, falls onto him, but when he sees Sam trying to take deep breaths to calm himself down, it softens. "I'm not yelling at you. Sam. You haven't done anything to deserve that right now." Cloying again, protective. "You wouldn't have let anything in while I'm away if you had the choice. No one else would ever make you whole like I do, and you know that."
"You're doing this," Sam accuses. The weakness from the trials might have given Lucifer an upper hand in this mental war. All of the things Sam has noticed, they're his doing. He should tell Dean. (Can he tell Dean? What if he tries and he forgets again? What if he thinks he's saying one thing and Lucifer makes him say another?) Lucifer looks insulted.
"No. Listen to yourself, Sam. You're smarter than this. If it was me, you would know." Lucifer reaches out a hand as though he can touch Sam's cheek. Even knowing he can't, Sam pushes his chair back.
Lucifer glares again, cuts through him. It's easy to tell which he's-
"-broke him in for my comfort, not yours," Lucifer is snapping at him again. Sam's head pounds. "Tell him, Sam. You belong to me."
"What?" He can't focus. He feels nauseous, jumping back and forth between Lucifer's tirades.
"Whose vessel are you, Sam?"
Without thinking, Sam answers, "Yours." He just wants Lucifer to be quiet. He can't hear himself think. Lucifer stills, a pleased expression crossing his face-
It's a scowl, and Lucifer looks like he wants to rip Sam to shreds. "Nothing you do will ever erase my claim on him. I worked him over too well."
"Shut up!" Sam shouts. A moment later, he regrets it, his voice echoes down the Bunker's halls. It doesn't work anyway.
"I took him when he was shattered across the floor of the Cage and remade him into something beautiful." Sam shakes his head. It makes his nausea worse, a sea too big to fit sloshing inside his skull. His skin feels too tight over his bones. Why is there so much inside him? It doesn't fit right, it's poking into his organs, stitching him together wrong. He's going to throw up. "He can throw you out whenever he wants. Do you understand that? You're an intruder. He never wanted you like he wanted me."
"Who are you talking to?" Sam demands. He thinks he's still shouting, but there's a roar in his ears. It sounds angry. He can still hear Lucifer perfectly, no matter how loud it gets.
"The angel you said yes to. His name is-"
Sam is sitting alone. Lucifer is absent for once, and Sam can work without the devil on his shoulder commenting. His stomach turns for some reason. He can't help the horrible, incessant feeling that he's forgotten something important.
But there's nothing there.