The first time Sam gets desperate during a hunt and makes a blessed silver knife move toward his outstretched hand is when they know something weird is going on.
Dean glares at him. “I thought you were done with that whole psychic bullshit,” he snarls.
Sam shrugs, because he thought he managed to be rid of the weirdness too, but here’s the obvious proof that that’s not precisely true, although he has no idea what, if anything, he did wrong in order to make this happen.
Still. They’re in the middle of a hunt, and Sam does have more immediate concerns to worry over. He uses the knife that’s causing all the trouble to begin with, stabbing the monster, and then a fight that had just been looking damn near impossible is over, then as the unexpected winners.
Dean is still glaring at him, has even backed up a few feet. “What the hell, Sam?” he demands.
Sam shrugs again, desperately. “Dean, I–”
“Save it,” Dean interrupts. “I’m calling Cas. And if we have to lock you down again…well, at least the dungeon should work.”
Sam shivers at the very thought.
Dean as this vicious glow to his eyes, one Sam would like to attribute to the Mark of Cain, but it was there years ago, when they went through this the first time, too. Sam doesn’t want to look his brother in the eyes, doesn’t want to see it.
“How can you think–” Sam begins, managing to summon some righteous anger through his fear.
“Drop it, Sammy,” Dean says, tiredly, like he’s the one finding out his life is changing, like he’s the one put upon. “Let’s go. See what Cas has to say, see what we have to do to sort your shit out again.”
Gnashing his teeth, Sam follows, if for no other reason than that he too is curious about what’s going on.
Cas looks Sam over, then shrugs. “I don’t know what you expect,” he says. “You were the one who allowed Crowley to shove needles into his head. It reawakened what has always been there.”
“So you’re saying this is my fault?” Dean demands.
Sam thinks Cas might even roll his eyes. “Sam being in that position was indeed your fault, Dean. But his powers are not. They are just a part of him, one he did his best to forget until Crowley’s needles woke them up. Just something Sam has.”
“He’s using them to keep you two safe. Not to kill people, or anything wrong.”
“Do you need a reminder of what happened last time?” Dean snarls. Sam flinches a bit.
“I don’t see a garrison worth of angels and demons trying to manipulate Sam into starting the apocalypse.”
Dean laughs coldly. “Cas, if you think–”
“Enough!” Sam shouts, sick beyond measure of listening to this. “You heard him. I’m fine. Nothing weird. This is just something I can do.”
Sam doesn’t want to hear it. He’s fine. He’s not doing anything wrong. Dean can spew words all day, but it won’t change anything.
Sam screws up his concentration and manages to summon a book from across the room to his waiting hands. It’s partially just to make Dean watch, partially so he can have a distraction, and he decides right then and there that this powers thing is pretty useful after all.