A/N: This was a comment fic for the November 2011 Sharp Teeth Horror meme. The original prompt was from the extraordinarily talented and clever honeylocusttree, and it can be found at the bottom of this page.
Time in hell runs differently: that's newbie stuff. It's not until you've been there awhile that you really understand how differently it runs.
Topside, there's a story about hell that goes like this: there's a man who asks for a glimpse of hell and is granted it. He walks through a door and discovers a torture room presided over by a horrifically twisted creature. The man turns to flee, but the creature pounces, ties him up, and subjects him to a thousand years of unimaginable torture. Eventually, the man breaks free and kills his captor. The body disintegrates, the door opens...and in walks his earlier, innocent self. In a rage, the man-turned-monster sets upon his younger self. Hell is nothing like that. It's worse. But there's a seed of truth to it. Some demon has been telling tales out of school, because the thing is- time in hell doesn't just run differently; it runs inside out. It's an eternal cycle of yesterdays and tomorrows. You arrived last month and a thousand years ago, you will arrive tomorrow. Time has no hold on hell.
Dean has had forty years (fifteen minutes) of blood and darkness, and two minutes (millennia) of blinding, nuclear fire before he is born into a new hell of burning dust and boiling mud.
Time here is a heavy, bloated sun that hangs perpetually just above the horizon, throwing the landscape into the purgatory of near-twilight. Dean's shadow stretches out long behind him, as if trying to climb back into the pit he lost four fingernails climbing out of. His is the only shadow on the wide, red plain.
He slogs forward through red mud. It's sterile, dead, but it smells strangely clean in an odd, metallic way. It splatters up his bare legs and slithers through his toes. He's covered in it from his ungainly birth into this world, clawing his way out before he choked on it. It stains his skin the color of old blood, and where it dries, it itches and flakes away. Dean wished it were blood. The hell of the rack and the tortured souls was a familiar evil, one in which he had his place. There's nothing familiar in this, nothing but the slow, aching burn that every breath leaves deep in his chest.
Nothing about this place changes. He walks and he walks and he walks, and the only sign that he's moved at all is the trail left behind him. Time here is measured in death. It's a novelty. The rack was all about bringing someone to that breaking point, the point where dying feels like a triumph, and snatching it away. It was a way of making even being whole and unharmed a torture in and of itself. Here, death isn't triumph. There's no victory here, just the long progression of endless days. Sometimes he succumbs to coughing, red blood mixing with the red mud. Sometimes it's a heart attack. Sometimes he gets so dizzy he falls forward and drowns in the muck. Sometimes his skin slides off his very bones. But every time- lights out. At least for a little while, and then he's reborn into screeching, burning light. Sometimes it's the light that kills him. He's pretty sure that part is unintentional. It's okay though: he's pretty sure he knows what it wants now. He's pretty sure it's trying to ask him something. He spends a hundred deaths trying to figure out what it might be before he realizes that it's pointless. It doesn't matter what the question is: Dean already knows his answer.
It's at least another thousand deaths before the thing does, too.
A/N: Original prompt: Time moves differently in Hell. So differently that when Castiel finally busts Dean out, he finds himself in a dead, dusty wasteland, a bloated red sun hanging in the sky. Every living thing (including potential vessels) shriveled to dust millenia ago, and Dean staggers alone through the desert, pursued by a shrieking, pitiless light.