Castiel had been riding on the backseat of the Impala when it broke down, his grace had been drained during their last fight with a lot of demons, so he felt much more tired than he should, leaning his cheek against the cold window and struggling to stay awake, they were in the middle of nowhere, and it was pouring outside.
As he watches Sam stand outside, holding an umbrella for Dean… he feels guilt gnaw at him, he should help too.
It's that thought that drives him to step out of the car, neither of the brothers notice him as he does, it's quite dark and the rain doesn't quite help either, so it's understandable.
He comes to stand behind them, stretching his wings out behind him for a moment before bending them forward, successfully covering the brothers and the entire car.
"What the-?" Dean startles before Sam notices Castiel standing there.
"Cas? Are you doing this?" Sam asks, curious. There's some sort of invisible shield redirecting the rain, making it dodge them and the car.
"Weren't you like, drained?" Dean questions, confused and also sounding like he was readying himself to argue.
"I don't need my grace to move my wings." Castiel tells as a matter of fact, rubbing his eyes tiredly. Father, he's so tired.
"Your- your wings?" Sam stammered. They look up, as if that will somehow let them see the invisible wings.
But neither can see a single thing. Huh.
Dean goes back to work and Sam closes his umbrella since it's no longer needed. Instead, he looks up again, how can his wings shield the rain but can't be perceived?
"How can you touch the rain but nothing else?" Sam blurts out.
"I can choose how much of them to slip out of the ethereal plane. Their shadows, their presence or corporeal."
"You can make them corporeal?" Dean's head snaps back to them. Castiel makes a face, as if suddenly realizing he said something he shouldn't.
"I can…" He looked away. "But we usually don't. It's… forbidden. Our wings have the tendency to drive humans mad. You could see and touch a feather, but you wouldn't be able to see them without going insane."
"Why?" Sam asks, curious, they have never truly asked Cas anything regarding angels. Though he does admit he has always been curious about whether he could make his wings corporeal or not. But he's never dared to ask.
"Humans can't handle true divinity."
"What's that supposed to mean?" Dean asks, feeling insulted. "Birds have wings too, what makes yours so special?"
"Do you remember how you felt when you saw the tree born from Anna's grace?"
Sam and Dean frowned at the odd question. Sure, the brothers remembered it, the tree had been beautiful, had made them feel lighter even. Right. Like staring at it forever…
"It's not our wings per se. It's our grace. What you felt for that tree was nothing but a small glimpse into what you would feel towards an angel's wings. And that tree didn't even have her grace anymore."
Neither said anything at those words. For a moment, silence was all that there was.
And then.
"Wait, if wings can do that to a human. How come the angels don't use that to fuck with us?" Dean asks suddenly. Castiel makes a face.
"Because to make wings physical, you would by extension be merging your true form with your vessel. It's not a particularly comfortable process. It's rather annoying and frankly not worth the effort." Very bloody too, way too bloody.
Not that anyone needed to know that.
"Does it hurt?"
"Some." Castiel states, looking at Dean as if he were stupid for even asking.
"Could you do it?"
"Why would I want to do that?"
"Fun." Dean shrugged.
"I don't see how that would be fun." Castiel refutes, he always had a hard time deciphering what Dean meant by 'fun'. His concept of it was rather… debatable.
"Why not?"
"It would be extremely uncomfortable for everyone involved."
"How come?"
"As I understand it, my true form can be unsettling for humans. Size aside."
"Meaning?"
"I'm a seraph. Our kind is covered in eyes, most humans find unsettling the idea of a creature covered in eyes. Why do you think the phrase 'Don't be afraid' appears so much in your Bible?"
"Touché. Though I still think it would be funny."
Castiel rolled his eyes, though he couldn't help but smile, he could only imagine how much Dean would take his words back if he were to see his true form.
The silence after that reigned for a while, that is, until Dean spoke again.
"Say, you wouldn't happen to have anything to use as a flashlight, right? Anything works better than Sam's poor skills at holding one." Dean said, getting a bitch face in return.
Castiel frowned for a moment before approaching them both, he came to stand next to Dean, bringing his hand up, and then his hand lit up, illuminating everything. For a moment, there was nothing but silence as the brothers stared at his hand.
"That works too." Dean conceded at last.
Sam had no idea how to feel about the fact that his brother was using an angel as a fucking flashlight, as if the umbrella wasn't enough. Dean even took it to grab his hand and lead it to wherever he needed more light. Cas didn't seem to mind, he seemed rather invested in Dean's explanation throughout the process of fixing the car.
And Sam couldn't help but smile in amusement, their lives had certainly become something beyond anything he could have ever imagined.
If anyone would have told him in Stanford that he would one day be standing in the middle of nowhere with an angel, who was also his friend, posing as an umbrella and a flashlight, he would have certainly questioned the person's sanity.