There isn’t a full AU for it, but there was a prompt way back a year ago that I wrote for Dean (It was called Cursed Dean at the time). I probably won’t be able to find the time to do anything more with it, but there’s the possibility of a collaborative AU with neon where Sam is the tall one and Dean is the small one.
Dean’s hand went to his amulet, the memory of his younger brother, big hazel eyes staring hopefully at him as he opened the gift coming back as clear as day. He would never risk taking it off, afraid of losing it to an errant gust of air, or slipping into a crack to vanish forever.
After all, that same brother was now a towering giant, wherever he might be. If he found Dean, he would simply catch his older brother and drop him into a cage. Maybe worse, depending on the way their dad had trained him. Dean would cling to those memories like a lifeboat, knowing he’d never see Sam again.
Those memories would never leave him, but here and now he needed to stay sharp. He came up to the end of the vent, suspended up in the air almost six feet. The design of the motel had never made sense to him, but who was he to question it?
No one would listen to a man that stood under four inches tall.
Dean leaned against the grate, staring out into the immense motel room.
The vertigo hit him, as it always did, but this was more important than his fears or the thought of getting teased because he was afraid of heights. Those eyes, seen so briefly in the room earlier, haunted him. Soft, familiar hazels that forced his mind into the past, to a time before he’d been cursed. So many years ago now… soon he would have lived over half his life under this infernal curse.
At the table below, the man that had checked in earlier was sitting with a dusty old book. One huge hand turned the page with a loud crinkle, smoothing it carefully down. Fluffy brown hair was scattered messily about, in clear need of a good brush. Dean’s hand went to his own hair instinctively, trying to fix his spiky style. Cutting it himself didn’t make it easy, but he persevered.
While Dean was distracted, he accidentally leaned too much of his weight on the grate. With a loud, echoing Creak! the air vent slid shut, sending him to his knees without warning. He slammed into the metal ground with a loud (to his ears) thump.
For a long, heart-stopping moment, there was nothing but silence.
Then, it came. The most terrifying sound he could have heard.
A shifting of fabric in the motel room outside indicated the human standing. “Hello?” rumbled a curious voice from outside, making Dean shiver once with worry. The human was tall enough to see into the vent while standing if he wanted to, and if he realized what was hiding from him in there…
Dean didn’t move, simply trying to wait it out. The human would just assume he heard the motel settling, just like anyone else. No reason to check the vent, no way to see Dean in there.
No such luck.
There was a creak from the vent again. The human was moving it. He needed to get out of there, now. If he got caught by such a huge human, the largest he’d ever seen, there would be no hope of escape.
Dean went to run, and fell flat on his back. His satchel! When the grate had closed it had snagged the strap, effectively trapping the small human.