I've got one for the burial mound: A while back I was vacationing with my family in the Caribbean... I was about 10-12 years old at the time. I was really skinny as a kid, rail thin, very weak looking... you get the idea. Anyway, I'd never really traveled before and I had absolutely no street smarts whatsoever. One night my family went for an evening boat ride, and by the time we returned to the dock it was about 10 or 11 at night. There were no lights on, it was pretty much pitch black.
This particular island (not going to name it for privacy reasons) was really really impoverished... like as in, people making less than \$1000 a year and living in run down little shacks. I wanted to be the first one back at the car, so I ran far ahead of the group in basically total darkness, I turn the corner to the parking lot and as soon as I do, a man grabs my arm very tightly. I was really confused and couldn't even see his face because it was so dark but he started asking me "Who drove you here? Who drove you here? Here, come with me, you're supposed to come with me. I will drive you." So he starts pulling me toward a van but right as I start resisting, someone turned the parking lot floodlights on and the guy looks up, startled, as the rest of my group came around the corner. He immediately let go of me and tried to play it cool but was clearly pretty flustered.
That's probably the creepiest thing that's happened to me. I think about it quite often -- I was so oblivious and naive at the time that I didn't really realize how sketchy the situation was until years later. If the group had taken 30 seconds longer to get there, I probably would've ended up in a really fucked up situation.