Always open to suggestions short of killing someone. LOL!
Pepper balls if you can find or make them.
Or rock salt/pepperdust quarterloads.
They way I figure, this dude has done nothing violent, yet. He is just trying to “scare” people by being creepy. He’s getting a good laugh. So fight fire with fire. Until it’s reported that he’s done something violent get out the paintball gun. Even if it’s a near miss, he will piss his pants while running. Then you’ll be the one laughing all the way home.