Ok, this one's long and wierd as heck and I believe it to be the result in getting my first good night's sleep after at least a week of nearly sleepless nights.
I had a dream a couple weeks ago where I inherited a huge mansion and a large sum of money from a dead relative, and the first day staying there I invited all my parents, relatives, and friends over for a party.
In the middle of the party everyone disappeared, and I realized I hadn't invited anyone to a party, but it was all an illusion from somewhere or something. I woke up in the mansion but there were creepy black humanoid-like creatures walking around everywhere so I hid in a corner. I picked up an odd book and opened it and started reading it spontaneously.
The book was somehow forcing me to read it in some unknown language! I could look around at other things and not look at the book, but my mouth kept saying things from the book uncontrollably. I was holding the book with one hand, and I could move freely except I couldn't drop the book and I couldn't close it either. Whatever was in the book was calling one of the creatures towards me! As soon as it spotted me and was slowly walking towards me, I was able to drop the book.
At that point I was cornered and defenseless. For some reason I instinctively reached into my jacket and there was nothing there, but somehow I thought I was supposed have a weapon with me and it was missing for some reason. I heard a little girl's voice laughing in a sinister way out of nowhere. I felt a finger poking at my back, and turned around to see none other than Remilia Scarlet.
Remilia grinned and said "looking for this?".
She held out a Heckler and Koch Mark 23, which for some reason I sensed was supposed to be mine. I was already in a panic so I didn't ask any questions. I grabbed it, turned around, and fired several shots into the black thing, which collapsed and melted away. I turned around again intending to talk with Remilia, but she was gone. All I heard was her voice in the air and she said "Don't be boring". Basically what followed was a lot of running through the mansion and shooting whatever the wierd black humanoid things were. However, no matter where I went it seemed like the mansion's rooms and halls were re-arranging themselves when I wasn't looking and there was no exit in sight. The walls were turning a light shade of red or pink, so I pretty much figured I was either in the Scarlet Devil Mansion, or some twisted copy of it.
Admittedly I was enjoying this at first and I guess any gamer would have enjoyed this to some degree, but after a while things started looking bad and any confidence I gained from having a weapon in hand pretty much got dissolved by the depressing horror of an endless maze of rooms.
Eventually I reached a dead end room and the door behind me shut. I opened the door to see that the hallway I came through was gone and was replaced by a room filled with black humanoid things and no to other doors or windows, I was essentially trapped in two rooms with a door in the middle with no possible escape. At that point I just about lost it and yelled "YOU GOTTA BE KIDDING ME! WHAT THE HELL DO YOU WANT! I JUST WANT TO GET OUT! TELL ME WHAT YOU WANT!" and several other phrases to that effect that I can't remember.
I spent my remaining ammo killing off all the black things except one. I backed into a corner, then decided at the last minute I had nothing to lose, so I attempted to punch it. My fist passed right through and I was pulled through the black humanoid thing and fell as if it were a hole or portal.
I felt a hard landing on a wooden floor, and saw Patchouli looking down at me with a rather amused look. She shouted "Wow I think he made it!" to someone else, who in retrospect I guess might have been either Remilia or Sakuya.
I looked down and saw my clothing covered in blood, which was strange because I didn't think I had gotten any physical wounds of any kind. I laid my head back and hit it against the wooden floor and immediately woke up due to my alarm clock.
Anyway, I of thought up a bit of a possible backstory in an attempt to explain this dream because I kind of want to write a short story or something based on it, but I'm not sure if I'll bother though since I'm not that good at writing.
I figured perhaps before the SDM was moved to Gensokyo, Remilia would lure people into the mansion and force them to fight through a similar "house of horrors". Those who didn't perform well would be food for Remilia and Flandre while if someone somehow survived long enough they would be hired to serve her. Perhaps Sakuya would have been brought into the mansion in this manner.