This happened in June, 1964. I lived in England on the border of Scotland. I was staying at my aunt's house, which was rather small, having only two bedrooms. I was using my 16-year-old cousin's bedroom, and his parents were in theirs down the hall. My cousin was downstairs sleeping on the couch.
I had settled into bed and could see the moon shining through the window. I heard a creaking of the stairs and surmised that my cousin was going to creep into my room and scare me. I waited, giggling to myself, with the covers over my head. I was going to wait until he got near, then I was going to yell "boo" or something.
I heard him turn the squeaky doorknob and heard him shuffling to my bedside. He was making soft grunting noises. When he got level with me. I whipped the covers off my head and screamed, because it wasn't my cousin, but a horrible creature with glowing eyes. It looked like a hunched up animal of some kind.
I dived under the covers and screamed again. My scream aroused the whole household. I heard my cousin thumping up the stairs, and my aunt and uncle came running into my room. They said I'd been dreaming, as nothing was seen in the small home.
I know I was not dreaming, and I never stayed overnight there again. Even thiough I visited many times, nothing else ever occurred, but I always felt uneasy.