Eh, I'd just write a bunch of really insulting and offensive notes on pieces of paper, addressed to your stalker, crumple them up and toss them in the trash. That way you get to tell the asshole what you think about them in a way that you can't possibly get in trouble for, since they would have to admit to stalking you in order to complain. If it is, in fact, your supervisor rooting through your trash, and he has a problem with it then fuck it. You should quit anyway.