This Skin is Not My Own

Mr. Valen woke to darkness, a regular occurrence by now, but it wasn't your regular type of darkness.

It was different, the kind that pressed from all sides, the kind that was alive.

'Was I not supposed to wake atop a tree?' Mr. Valen was forced to ask himself, as the last thing he remembered was falling asleep in a large tree.

Whatever he remembered, though, was rendered irrelevant, as the current issue prevailed:

He could not move, and any time he tried, the pressure around him tightened, like a vice squeezing his entire body simultaneously.

A tentacle, or something akin to one, coiled around his chest, arms, and legs, making each breath a labored struggle. 

"Crunch!"

Suddenly, his ribs creaked, and something oozed across his skin, thick, sticky, and burning.

It was acid, or at least it felt like acid—corrosive.