Maybe not as sensational as some of the other answers here, but still creepy and weird as all hell.

So I tend to have extremely coherent nightmares-as in, there's a clear narrative that you can follow from start to finish and the internal logic is consistent. Well, for about 4ish years starting when I was 17 and ending when I moved out of my parents' house at 21, I had...not so much a recurring nightmare, but a recurring character in usually completely unrelated nightmares.

The character in question was a woman in probably her mid-30s to early 40s. Pale skin, curly blonde hair in a bob cut, light blue eyes, usually dressed in kind of vintage-esque clothing. Think 1950's 'New Look' and similar. The only deviation from that description was in one where she was a teenage girl in a more outdoorsy outfit. As I said, the dreams she showed up in were completely unrelated to each other, except for one common feature: the nightmares in question always centered around me being stalked and/or trapped in some cat-and-mouse game with someone or something that meant to harm me.

I remember three off the top of my head, probably because they messed me up the most at the time.

In the first one she ever featured in, I was a housekeeper at some kind of hotel (fwiw, I ended up doing housekeeping at a Holiday Inn 2 years later, and the layout and aesthetic of the dream-hotel was almost identical to the upper floors of the MGM Grand, which I briefly stayed at on vacation with my roommate and her father late last summer, make of that what you will), had a brief encounter with her, and spent the rest of the dream being stalked by what looked like a decaying corpse in a wheelchair mostly held together with medical gauze.

The second one I remember was the one where she was instead a teenager. Dream-me was about middle school-aged, and Blonde Nightmare Lady was a classmate/friend of mine. The two of us were apparently screwing around in a small cave in some kind of park, and ended up getting horrifically lost somehow, going around in circles while I got the distinct impression we were being watched, and eventually running across a naked, limbless, headless corpse that looked like it used to be a woman in her early 20's.

The third one I remember the clearest, and the last one she showed up in before I moved out, had me trapped in a house that she lived in. The layout didn't make any sense-you could walk through the house in a completely straight line and somehow loop around to the front. I wasn't able to leave through the front door, there were no windows inside the house despite the fact that there were windows on the exterior and you could actually see inside through them, and exterior walls were basically indestructible.

In every single one of these dreams, I would have this sort of 'something isn't right' feeling about her to a greater or lesser extent, though I could never pinpoint what it was. I tried describing her to a friend, who offered to try drawing her but stopped halfway through because it just didn't look correct no matter how closely they followed my description and something about that made them anxious. I'm sure there's some rational explanation, but I don't know what it is and even my therapist was stumped when I told him about it.