A few years ago I was working in another country and the company put me up in a small hotel. There was a swimming pool in the basement so on the first night there I went down to check it out. I was the only one there, but the area itself felt fine and I didn't feel nervous or scared about being there alone. Actually the opposite as the pool was really quite tiny - only about 25 metres long, and any more than two people would have been crowded.
The room, whilst in the basement, did have windows high up on one side = the building was on a hill and the land at the front of the building was higher than the back, if that makes sense. It was still light out and the daylight was coming through the windows, although there were lights on as well. The effect, with the sunlight, was that the area of the room I was standing in, at the shallow end, was lighter than the deep end which was a little darker and had a few shadows. I started swimming, but as I got to the middle of the pool for some reason I started feeling worried, and almost as though I didn't want to swim any closer. I did swim the whole length, and then swam back again immediately. I got out and had a look, and the only thing I could see was there was a long shadow which cut across the corner of the pool. It was very obviously a shadow - this wasn't a case where it looked like something else out of the corner of my eye, but still, when I tried again to swim a length, it seemed to just emit something that made me not want to swim over it. I'm a confident swimmer, and the pool wasn't very deep, even in the deep end, and I've not had a reaction like that before in a pool.
To this day I don't know what it was, but I honestly felt like I didn't want to swim over the shadow - like it would come and get me. I tried swimming around it, but it just still seemed to be there. In the end I gave up and went back to my room. I couldn't bring myself to go back there.
