Put nails under all 4 of his tires, take a screwdriver and loosen his chairs, steal his pens, mess with his computer (if he has one), do anything you can to make his work life hell, while also kissing othe co-workers asses to get them on your side. Then get a friend to come in and tell the owner that your boss tried to sell him gear. The angry stares/quiet intimidation is good. You could also send a big friend in there to corner him and give him the classic "if you fuck wih my friend you're toast" speech. If you've done all that and the guy hasnt quit or is in jail or an asylum, simply confront the owner about it, being as reasonable as possible. If he is an ass about it too, call the Better Business Bureau and file a complaint, and get all of your friends/family to do it also.