I had these strange experiences when I was a child.
I would Wake up at night only to find out I couldn't scream, and then someone (dressed up as a person with a white table cloth around him) came into my room and put me in a bag, I did not only have these episodes while in my bed but also when I was playing. I could never understand if it was fear that let me see this "someone" but I certainly felt frightened. It was a feeling that I was very small and meaningless or that this "someone" became very big, I had this until my 12th year, than it stopped, we moved to another house and I never had these episodes until my 16th year, I made myself scared and then it happened again, that "someone" came into my room, grabbed me and put me in the bag and I couldn't scream, suddenly I had a knife and cut the bag open, then I asked him why he did it, and he couldn't answer, I woke up. All these years I wanted to know what triggered this and why I was so scared, I couldn't find out, and still can't. I know me and my younger brother suffer from Night Terrors but I believe there is more to it.
I will explain what has happened to me throughout the years.
In the first house I lived, there were 3 floors, my room was on the lower floor, and almost every weekend on a Sunday morning (around 6), I heard stuff falling from the stairs, and right next to my door, when I jumped out of the bed, there was nothing there. After a couple of times I asked my parents to sleep on the top floor, where those "kidnapping episodes" began. My older brother went into that room, and he once experienced a weird tapping on his shoulder, he was too afraid to turn around, he also heard stuff falling from the stairs.
We lived there for 12 years and then we moved to another house that was new, things went well and on one evening I was standing in front of my book shelves and I felt someone give me a push in my back, I fell against the book shelves and thought it was my brother but there was no-one there, I ran from my room and was too afraid to return. I only had 1 episode after that, which I described above.
At 27 I have my own house, it was almost 80 years old, I always had a strange feeling in the hallway on the top floor, and I am still not very happy to walk there without the lights on, but later more on that.
One night in my room I woke up, looked to the left, and someone was standing next to my bed, due to the lack of light it showed up grey, I couldn't describe a face but I know he had like floating clothes on, as soon as I screamed he floated towards me, over my head and into the wall outside. My former girlfriend asked me what happened, I explained but she said that it was a dream. I told her, that if it was a dream, why was my dog staring to the same exact place as were this "ghost" flew through my wall, she couldn't explain.
It has been a while since anything happened, I am still afraid in certain parts of the house, I cannot sleep with my door open, or without clothing lying on my chair, on many occasions I see someone staring in my room (when the door was open) but this year I had the strangest experience.
I woke up, and walked out of my bedroom, in the hallway I can turn left to the bathroom or to the right to my daughter's room but suddenly there was a door right in front of me, I still had a feeling that someone was watching me, it suffocated me, I was really scared, I walked into that door in front of me and I woke up again in my bed. And again I walked out of my bedroom, and to the left into the bathroom, we have a little children's bath and my daughter was sitting in it, playing with her toys, but I almost didn't notice it but next to her, was another kid, all pale, curly hair, looking at me, with sad eyes, I got angry because I didn't know him, and I was scared of him but I when I wanted to grab him, I felt sorry for him and I woke up again.
I still do not understand if I am dreaming, hallucinating or something else, but there were more people that got strange vibes when they are in my house on the top floor, the ex- girlfriend of my older brother once slept on the top floor and was scared throughout the night.
Maybe I am too much of a sensitive guy, I don't know but what I do know is that my daughter recently became as scared as me for the dark, she never had problems with the house being dark but now she is really scared, she is almost 3 years old but told me stuff that made me think if we are alone in this house...