Written for challenge #115: Unidentified object. I'm not sure this works, tbh.

Castiel couldn't imagine anywhere he would rather be than right here, now, with Dean sleeping serenely in the cradle of his arms and his wings. The sheer contentment he felt at just feeling Dean's skin against his own, Dean's warm soul peaceful at last, cradled in Castiel's grace as it was always meant to be. Beneath Castiel's left hand, Dean's heart beat strongly, feeding a life that Castiel prayed would last for many years to come. His right thumb traced the outline of the scar that had nearly spelled the end for both of them. And around Cas' neck, pressed between their bodies, lay the amulet, the thing that had inexplicably led to this epiphany from both of them, this miracle that had left them both at peace.

.oOo.

Dean stared at the still-toasty thing as it morphed before his eyes, now glowing with a clearly recognisable light that curled between his fingers gently, like a lover's touch. Like Cas' touch on his other hand, the threading of fingers that had begun the split-second before the thing had changed and started glowing in his hand. Grace was supposed to burn cold – that's what Sammy had told him – but this was warm, and if he were prone to anthropomorphising things, he would have said it was friendly and recognised him.

"Cas?"

Cas' hand tightened around Dean's left fingers painfully. His eyes were transfixed by the tiny piece of grace curling around Dean's right hand possessively. The disbelief, the longing were evident in Cas' expression.

"Cas?"

Cas was shaking. It was subtle, but Dean could feel it in their joined hands. Cas was trembling, and he wasn't blinking when he looked at the pure light that was starting to creep its way up Dean's arm. And the weirdest thing was that Dean wasn't worried about that at all, because he was pretty sure he knew…

"It's mine."

Two words from Cas. Two croaked words that changed everything. Two bittersweet words that were the difference between life and death to Castiel.

"It's mine." Incredulous now, with more than a hint of yearning. The very thing Cas needed had been delivered right into their very hands.

Dean reached up with his right hand, into the small space between them. "Take it," he instructed.

Cas shook his head. "It appears to have a task to do," he said, a smile starting to blossom, to light his eyes. He pushed Dean's sleeve up with both hands, and they watched as the creeping, tingly grace reached the Mark. Instead of shying away like Cas still instinctively did, the grace covered it entirely, covering it in beautiful, shining blue-white instead of the ugly red it really was.

Dean felt his breathing pick up as the grace whispered to him, asking him something he knew he would give the opposite answer to had it been anyone else's.

"Yes."

Castiel's eyes widened as his grace seared its way into Dean's arm through the Mark, burning through his every cell. It should hurt, he knew, but Dean was made to take the grace of the oldest and strongest of all the angels: Cas was awesome, but he was no Michael in the grand scheme of things, even after his promotion, or his soul binge. The grace of a seraph – his seraph – traced through every nerve, every capillary, cleansing him of the demonic taint he had carried for so long. He could feel his skin tingling with it, his eyes glowing as Castiel's used to. There was so much power coursing beneath his skin, Dean felt like he could do anything.

But it wasn't his, this power. It belonged to Castiel, and as much as he was loving having a piece of Cas all of his very own, his angel needed it more. This was the only thing that would keep Castiel alive and by his side for the rest of eternity.

So he cradled Cas' head between his haloed hands, pressed their lips together and let go.

.oOo.

They investigated, because that's what they did. Dean wished he knew what had possessed him to pick it up, because that was clearly insane. Particularly when Cas and Sam were telling him it was slightly psychic. Especially since it seemed to like him more than either of them.

He wished he knew even more why it had broken down the barrier he had around his feelings for Cas, and made him reach out for the angel, wanting to tell him everything.

.oOo.

"So what the hell is it?"

Sam shrugged. If he could get a good look at it before the damn thing shifted shape again, he might have been able to give Dean and Cas a heads-up before he brought it back to the bunker. He hadn't even dared touch it; picking it up with a pair of latex gloves just in case it was cursed. Which it probably was. The only thing that had been consistent about it was its temperature.

"It's hot," he said, lamely.

"Its temperature has decreased by three degrees since you returned," Cas noted with his typical bluntness. Thing seemed to like him: whenever he put a hand close to it, to feel it out with his diminishing angel powers, it seemed to purr and shift towards him. But it shied away if he actually tried to make contact with it.

Dean sighed heavily and rolled his eyes. "So it's hot but cooling down. Anything, you know, else, geniuses?"

"It is cooling a lot more slowly than one might expect," Cas added. "Its specific heat capacity is enormous."

"It hangs on to heat a lot more than it should," Sam explained for Dean's benefit. That much was true – he had pointed a thermal imaging device at it (and he wondered just how the Men of Letters had gotten hold of one of those), and it had clocked in at almost one hundred and sixty degrees, but he had been able to touch it with nothing but latex gloves. Sure, it had felt hot, but not burn-on-contact hot.

"So it's weird, hot, shy, and likes Cas," Dean summed up. "Wow, that's a lot to go on."

So it was one of those days, Sam surmised. Dean was going to be a bitch about probably everything. Dean blamed it on the Mark of Cain, but Sam knew that Dean had been like that even before: the Mark had just made things worse.

"It has a psychic presence," Cas interjected with a little frown. "It is not concrete, but…" A hand fluttered against his temple in a very human gesture of frustrated concentration. "There is definitely something abnormal."

Sam was glad Cas had mentioned it, because he hadn't wanted to say that he had sensed the thing's presence, just off his normal jogging route, that it had seemed to call to him.

The thing of it was, it didn't seem dangerous. It seemed… friendly, almost. Familiar. Even though Sam was sure he had never seen a colour-changing, shape-shifting, slightly incandescent blob before.

"Perfect," Dean growled. "Just perfect."