Animals learn from punishment, some faster than others. A friend had a college roommate who would rummage through peoples' things, sometimes when they were there (like my friend) as soon as he would walk into their room. Steve, who was studying electronics, came up with an amusing way to stop this by charging a large, square electrolytic capacitor to about 400VDC and leaving it under the newspaper that he, not the roommate had subscribed to. Bob would see the hump in the paper an explore, finding the cap. He picked it up and examined it, with the legs pointing up, then flipped it over so he could see the other side. When it landed in the palm of his hand, it discharged.

Good times! Bob was mad, Steve was amused and Bob wants to get together for a drink. Don't be like Bob- he must have forgotten.