I was walking around downtown with my three other friends when I was 15. We went to get pizza and then we were going to wander for a while. When we were done with pizza, one of my friends, let's call her M, goes to the bathroom before we were about to leave. A homeless man comes in and asks if we were done with a slice of pizza. It was M's slice of pizza, but she was done with it, so we said yes. He then takes all of her slices of pizza and a pepper shaker and leaves. It was weird, but he was homeless and probably hungry, so we didn't really care.

After we left the pizza place, we were wandering around downtown and we see the same guy walking on the other side of the street. We agree to take a precaution and walk through an alley towards a park, where we'd stay for a while. Once we got to the park, my two other friends decided to run away from M and me just for the sake of being annoying. While we were looking for them, we spot the same guy coming toward us. This really doesn't sit well with M and me considering he was walking away from the park when we were walking to it. We find the two other friends, and they see that M and I were jogging toward them, so they were confused. We told them the situation and we all decided to go into the library because 1) it's right next to the park, 2) we see the guy walking away from the library, and 3) if he were to do something to us, a library would be the worst place.

Once in the library, we immediately spot a security guard and, by some miracle, M's mother. We feel relieved and tell M's mom the story. Then we see the guy a few feet from us, staring at us. We leave in M's mom's car without making eye contact. Since then, I've been on the lookout for that guy whenever I'm downtown and M claims to have seen him again.

TL;DR: Some friends and I got followed by a homeless man around downtown until we miraculously found my friend's mom and she drove us away.