You may need a restraining order my friend. lol

I have never run across anything like this! This is funny but at the same time if it was happening to me I would be pissed! Dunno what else you could do besides an order against him. Maybe that will let him know that you are serious about the whole situation.

Maybe call him and ask him what he is trying to accomplish and see if you can come to some sort of agreement?... Maybe just go through explaining how the jet ski is now yours and you've titled it in your name and how you paid him for it. I deal with all different types of people. Crazies, rude ones, mean ones, happy ones, sad ones, etc... There are some crazies that just don't get it but if you try and talk it out with him maybe it will make sense to him. Maybe he just wants somebody to talk to. It seems he may be doing it for attention? Just give him a little attention and this will all be over with.

On the other hand, giving him attention may add "fuel to the fire". lol. You are in a predicament. Call the police non-emergency number and ask what you should do. They are usually good about what to do. And, probably better than my analogy of a crazy person above ^^^. lol. GL.

Let us know what comes of this.