For a few years we lived in a very shabby old house, with holes in some of the walls, including the one by the staircase. There were always mice, and there had been rats at one time. My room was upstairs, and it was kind of dark and creepy anyway, and I was always convinced that there were rats behind the lath on that stairway, waiting to bite me as I passed. Outside my room there was also a sort of open hallway used for storage. There was a big old radio amongst the junk, and for a long time I would look out my door and see a faint reddish glow, and be convinced that it was a fire starting and the house was going to burn down. Finally after many nights I got up the courage to go out one night, and found that beneath the radio was a little hole in the floor, and the light from below was reflecting off the radio. I was about 5 when I solved the radio mystery, but until I was 7 and we moved I always ran like hell up and down those stairs!
When we moved, we got a nice house in the woods, and one of the first things I heard was a neighbor warning us about a rabid fox he'd seen roaming around. For some time I was convinced that this beast was going to find its way in my second-story window. I got over that, but always found the woods creepy at night. In my teens, I finally said "this is silly," and went out in the dark for a walk in the creepy woods, and within about 50 yards came face to face with the biggest owl I've ever seen. We both decided to try someplace else that night. A few years ago in the same woods, my mom was wading in her pond, accompanied by her dog and cat, when, in broad daylight, a coyote came out of the woods and carried off her dog and ate it. I still find those woods a little creepy after 50 years!
When I was little, I was also creeped out by apples that turned brown in the air. I couldn't make myself eat one even though I knew they weren't really rotten. Also by milk that a fly had fallen into, but we couldn't afford to throw it away, so I usually ended up doubly creeped-out by having to drink it 3 hours later, not only ex-fly but warm!