He's not trying to be threatening or anything, he's just really really annoying. He's like Spike, actually - he only wants to play and doesn't get that some kinds of play can do harm. And he does stop when I raise my voice a bit - it's just that I need to do it every single time I encounter him and it gets annoying.

I think the police would be an overreaction (in this particular case; I'm not saying you overreacted) but once I work out which one his mother is I shall have a quiet word with her, I think.