I was with a few friends of mine, looking around in my home town. We were, at the time, into all of that "paranormal" stuff. All we wanted was to find something, evidence of... Well, we didn't quite know. So, we were a few blocks away from my house, at the creek down the street. Now this creek always had a heartbeat, so we thought it may have been a good place to look. Now, for the "Heartbeat", I'll get back to that in a minute.
The creek lead out of a sewer. We called it the "Creek of Death" because a lot of bad things would happen there. My older friends found a dead hen there. There were no hens where we lived. I also heard a story of a kid who used to live in my house. He went into the sewer area with a couple friends. Later on, he was found at the entrance with his head cracked clean in half. He barely survived with surgery. The other kids were never found.
So, whenever you go over to the creek, if you listened really closely, you could always hear a quiet "Thump... Thump... Thump..." It happened every about 25 seconds, and never stopped. I remember one time, a bunch of white fluid came from the sewer. At the time, we thought it was just that someone had dumped something in. Now I know better.
So, back to the part about my friends and I. We were at the mouth of the sewer where there were always thumps. It was... Dark. Pitch black, in fact. I knew my town well, so we knew where the sewer grates were, and in turn, where the light was going to be. Just in case, though, we brought a single flashlight. That was a HUGE mistake.
I ALWAYS carry a pocket knife with me, even at school. I thought we'd be fine... So we went into the sewer. After about thirty seconds of walking, the thumping got louder. Then, the entrance we'd gone through faded to black. Everything did, even the friends who were right next to me. The entrance did, the little grates through which light shined through... Were all... fading. Since I was kinda the leader of the group, I turned on my flashlight, which had been working before. It looked like the battery had quickly died right as I turned it on.
I couldn't see a thing. I was always a little bit afraid of the dark, but this was different. The thumps were getting closer. I pulled out my knife, but then something slapped it out of my hand. I blacked out. I woke up a little while later with something breathing on my chest. It was big, and... kinda slimy, for lack of a better term. My knife was gone, my flashlight was gone, I was covered in sewer water. I didn't know what to do. Then, suddenly, I heard what sounded like rain. Whatever it was that was on me, flipped out. It didn't like rain, whatever "it" was. Somehow, I blacked out again. Right after I could see again... It seemed like this thing could black out my sense of sight and then I would just fall asleep.
I woke up awhile later, with my friends, outside the mouth of the creek. They said they didn't remember what happened, and I kept to myself about what I saw. That thing scared the living shit out of me and I never wanted to talk about it again. I had a bad gash in my arm and I was bleeding badly. After a little peroxide and some gauze, I was fine, but something had to have caused it... And I don't want to know what.