I was on a hiking trail … I could see at least 50 meters/yards back.
I stopped and took a couple pictures of some deer super close to the trail. Looked back, then kept walking… Nobody there.
A matter of moments later, I hear footsteps behind me. I had headphones on but I wasn’t playing my music very loud. I take a quick glance back, the guy is wearing a grey T-shirt, a blue ball cap, blue jeans, and white sneakers. Literally the most generic outfit you can possibly have and he’s looking at the ground so I can’t see his face.
I decided to call my friend who’s always home on my phone. He picks up and I just start some BS conversation. Probably 15 seconds later, the dude vanished just as quickly as he’d come.
I don’t know if he was just a really fast walker and my situational awareness was way off that day, but it did freak me out.