Nightmares, you say?
This one's a gem, I had it a few months ago. I'll try to do it some justice and tell a good story. This dream has the distinction of having been vivid enough that it was barely distinguishable from reality, even in hindsight. I'm not sure I've ever experienced a dream so vivid before.
In my dream, it's late at night and I'm alone in the house. It is completely silent save for a loud ringing in my head, even the constant roar of the nearby ocean is absent. I can't possibly describe the feeling, but something about it is unnatural in a way that makes me feel ill. The emptiness seems to have an almost life-like quality to it and I feel like I'm being watched, and that something dire and inescapable is going to happen. But I don't know what.
Out of the emptiness I hear a clunk and the chime of a grandfather clock. There is and has never been such a thing in the house. The sound seems to come from no direction in particular, its acoustic qualities are at odds with the shape of the room. Like the silence before it, it is entirely out of place. It seems to announce the arrival of whatever inevitability it is that stalks me. I can say without any doubt that it is the worst sound I have ever heard. It's such a simple thing, but hearing it fills me with a kind of paralytic dread.
I hear a loud, rhythmic banging on the door, like someone is half-heartedly trying to force their way in. In any other circumstance it would be threatening, but I'm just glad to hear something other than silence or that awful clock. It's a natural sound, something that can be understood. Hearing it actually comes as a relief. The ringing in my head has stopped by now and I can hear the ocean again, which is doubly re-assuring.
I open the door and I'm nearly bowled over by my dad, who has for some reason stopped by in the middle of the night. I notice immediately that something is wrong with him. He's swaying on his feet as if he could collapse at any minute and foaming slightly at the mouth. He's carrying an enormous dripping paper bag that's completely soaked through, which suddenly rips open. Out onto the floor spills a slippery pile of raw meat and sausages in every variety you can imagine. It's more than anyone can possibly eat and it's clearly long since thawed in its entirety, is looks as if he has gathered it out of compulsion. He seems incredibly weak and sickly. He clutches his head and tries to say something but it only comes out as a series of unintelligible moans and wails. By this point I gather that he's suffering some sort of disease. I try to step forward and help him somehow, but he snarls as if he's going to attack me and then breaks down crying. He's obviously not in control of his actions and it's incredibly disturbing to witness.
The dream skips ahead. I'm informed automatically and intuitively that I'm in a hospital searching for a cure for his disease, in that way that dreams do. It's more than that though, I know with complete certainty that the hospital is responsible for the disease in some way. The hospital seems to be have been abandoned for some time now. The silence is back, and with it comes the feeling of being watched again. I'm on an upper floor and it feels like I have been running through its corridors for hours. (I can't remember much about how it looked except that it was incredibly grimy and decrepit, only about half the fluorescent lights hanging above were working and those that did work flickered unevenly.)
I begin to slow down as I sense that I'm closing in on the answer. I stop in the middle of the hall almost involuntarily as if I had reached the edge of an invisible cliff and look to my left. I see a large, transparent wall built out of something that looks bulletproof with two sliding double doors of the same material standing agape. Inside is a dim, blinking red light on the far wall but it's too dark to see anything inside. I enter despite being unnerved by everything that has happened so far.
The second I pass through the doorway, the red light shuts off and bright white fluorescent lighting switches on from the ceiling. The doors slide closed behind me with a heavy locking sound. In the middle of the room I can see about a dozen or little boxes I can't see into completely, and I realize I'm in one of those maternity wards. The sound of shrieking infants fills the room as tiny, bloated and black arms rise vertically into the air from out of the box-beds. I can't convey the subtleties of the exact motion used, but the way in which they moved was sickening. I panic. I try to break through one of the transparent doors but as I suspected it's made from a highly durable material. What can only be described as black, writhing tendrils creep out of the beds and spread over the floor, feeling around the room.
I woke up at that point sweating profusely and didn't sleep until dawn. If you read all of that, congratulations! I hope it was worth the read to you. It sure scared the heck out of me.