The ache in Remus’ bones is immediate and familiar, even after so many months without: he’d choked briefly on the thick fog he’d wandered into then choked, on the pain lancing up his spine as much as the changing landscape of his throat. He has moments, and only moments, to panic, to wonder what happened, what changed to bring this back, what he'd done to--to deserve it, before his spine shifts and his jaw grows and he's falling over and his skin is hardening into dark, thick pads on his palms--
moments before the panic becomes a detached appreciation for the design of it, the way it happens in such specific order that his teeth lengthen and point without ripping through his skin--
and the dullness is a blank space in his mind for the hunger and hate and madness to flood into. Colors are replaced by scents and flavors and these too are familiar, not the rich palette of the island but the musty, earthy stink of the shack, the root-bound tunnel and decaying furniture that was new, that first year, that he tore to shreds and splinters more easily eaten by the damp.
He's standing--crouching, snarling no standing on shorter legs at the door, shuffling as he acclimates to the body when the handle starts to turn, and maybe there's something of him left in there after all because Snape is a greasy smear of chemical and herbal scents and James is a purer kind of sweat behind the film of it and an acid sick feeling moves through Remus like it's funny.
The best part, though, the best part is how both of them smell of fear, that sharp sallow piss smell like the cheapest, clearest alcohol, it tastes like paint thinner and makes him salivate like the charcoal fat smell of meat dripping into a fire, drives him mad and he was already well on his way before--
before the flesh of Snape's arm is popping and ripping under his teeth like the skin of a grape and the paint thinner runs a little thicker in his nose, mixes with the tang of blood and his hearing is so much better, so much more acute that Snape's cry shivers through him like a touch until he paws the pale sick smear of him down into the dirt and tears out his throat.
That part, that--it isn't so familiar, but what he is now doesn't care, what he is now keeps tearing at the thin muscles of a dead man's shoulder just, just to do it, just to rip him apart and the crack of a spell isn't enough to pull him away from the task until it literally knocks him back.
His head whips up, the sweat-fear-sweat-smoke smell of James dances back and forth in the tunnel, his feet kicking up little red flurries in Remus', in its mind because no, no no you never run from something like this. Something built to chase.
The cry James makes when Remus gets him by the calf, when he drags him into the dirt, is too breathless and muffled to touch him at all, but every growl and grunt from the delicious effort of chewing through so much more muscle and fat and yes yes yes snapping tendons, they vibrate down the tunnel like sounds in a bigger, longer throat.
If he moves now he can slip through the tunnel and into the night, he can do this over and over, he can do exactly what he was made for.
He's the only thing in the tunnel left breathing, long, gusting bursts from his blood-soaked muzzle, and every inhale reeks of it and makes him pant harder.
He walks over James' body and moves toward the fresh air of the grounds.