It was late at night, maybe 1:30 in the morning. I don't remember how I got there, but I was standing on the shore next to the river that passed by below town. The bridge above me seemed to extend into the sky higher than I thought possible, standing tall like a concrete titan. It was apparent that I had driven myself down to the river, as my car was parked on the side of the road nearby. But I don't think how I got there is awfully important. It's what happened next that's interesting.
I must've slipped on a rock or something, because next thing I knew I was face-down in the river, floating downstream. Half-asleep and recovering from the shock of slipping, I couldn't get my bearings straight to keep my head above the water. The current from the river pulled me under, and my vision was consumed by the blackness of the water. I felt something pull on my leg, and tried to fight back, but I passed out before any progress could be made.
Waking up was a shock. I wasn't on the side of the river, or in my car, or in my bed, as though the whole thing had been a nightmare. I was in a cave. The walls were lit with some sort of luminescent slime, casting just enough of their electric-blue light for me to see the pool of water at the far end of the cave. I tried to stand, but my back, legs, and shoulders were covered in a warm, sticky substance. When I went to wipe it off, it retracted on its own, as if it were alive. I managed to stand, and turn around, but there was nothing there. The light from the slime didn't reach this far in, so I was left confused as to what was stuck to my back. A small glint of light hit my eye, as if the blue light of the slime was reflecting off of something. I reached my hand out to where the reflection had been, and I felt something hard. At first I thought it was just a shiny stone, but the sound of movement after I pulled my hand away told me that I thought wrong. The shape extended in front of me, almost reaching the top of the cave, and moved forward into the light.
When I first saw her, I was terrified. Her face came into view first. The top half was that of a human skull, but the bone was pitch black. The empty eye sockets stared at me as I examined the rest of her face. The lower half had flesh, covering the jaw, chin, and mouth area, with a strip extending upwards onto the skull, covering the spot where her nose would have been. The flesh was an inky black, with dark red swirls coursing throughout her complexion. Her mouth was open. At either corner, there were two strips of skin connecting the top and bottom of her mouth, locking it into the open position. But the most horrific part of her face came into view next. Instead of having lips, or teeth inside her mouth, the top and bottom edges were adorned with shiny metal strips, with pointed edges of their own, akin to a blade on a bandsaw. The metal strips were bolted into her skin, presumably with another piece of metal on the inside to hold them on. Fear was all that I knew at this moment, and it was strengthened when she began to speak.
"You're awake," she said, sounding concerned for me. "I didn't expect you to get up so soon."
Her voice was soft and gentle, but considering the source, still terrifying. No part of her mouth moved while she spoke, the sound just exited her face like a tunnel, giving her speech a sort of hollow feel. I wanted to respond, but my fear had caused me to become transfixed on her face. Unblinking, since there were no eyes.  Unmoving while she spoke. Yet, her face still managed to show emotion, somehow. She was concerned about my well-being.
"You're scared of me, aren't you?" she asked. I managed to nod my head.
"I saved you from floating down the river and waking up dead." I nodded my head again, and tried to puff out a "Thank you", but I had no such luck.
I didn't notice that she was moving closer at first. Only when she made contact with me did I snap out of my trance and realize what was happening. A crumbling, clicking sound started, drawing my attention down to her lower half. As human as her face was, her legs did not follow suit. Tracking along the floor of the cave was a massive, centipede-like body, six feet in length, with a hundred legs on either side. Hard shells covered the top, with intricate designs decorating it in black, dark red, and dark blue. Along the sides were several dome shapes, giving off a sickly green glow as the legs made their way across the cave floor. The clicking sound was almost thunderous now that every leg was in motion. As she moved further into the light, her top half became visible as well.
Her upper half stood nine feet tall, from the top of her skull to the connection seam with the centipede half. Her face was at the top, as you'd expect, and her anatomy down from there was quite humanoid: a neck (that might be just a touch too long), two shoulders, and a chest, topped with two featureless breasts. Her arms extended down from her shoulders, but at the elbow, split into several long, flowing tendrils, that seemed to move on their own. She reached her left arm out to me, holding the tendrils closely together, forming a fleshy point at the end.
"I'm not going to hurt you," she said. "The river would have done that quite well enough."
She motioned with her arm towards herself, as if to say "come here". As I approached her stomach entered my field of vision. Rather than a smooth, fleshy, human stomach, she had a large pit, extending back into her body. The flesh of the pit was dark green, and circular rows of teeth decorated the pit. The green flesh moved and gurgled around inside her body, bringing back memories of the sarlacc pit from Star Wars.
After I had stepped close enough, she held me close with her tendril-arm. "You want to leave here, don't you?"
"Yes," I said, stumbling over the word. She picked me up in her tendrils and held me up to her chest. Her skin was warm, and stuck to my face when I rested against it.
"Take a deep breath," she said. "And hold it."
I filled my lungs with air, and heard her legs click-clacking against the rocky floor of the cave as we splashed down into the pool of water. I shut my eyes, and let her carry me back through the river to the shore.
She set me down on the sand, and I looked back up at her. I smiled, and she began to sink back down into the river.
"Wait," I called out. "Do... do you want to... come with me?"
She turned back to me, and hesitated for a second.
"Yes," she replied.

It's been five years since that night, and I think she's already climbed into bed. It *is* getting late, so maybe I should go join her.