We have my car, the cat's food/water bowls, and the cat's litter box in the garage. My cat has a habit of going onto the car when I am not around and running off as soon as he hears me coming because I make a big scene trying to scare him from getting on the car again. I have tried placing floor mats upside down on the windows but the spikes don't bother him one bit. As I said before, I can never catch him any more because he jumps off the car every time he hears me coming toward the garage. I'm about ready to force him to start using the back yard as a litter box since he has created a hole in the screen to escape the house and become an outdoor cat any way. Any suggestions if he already knows I don't like him on there and my spikes on the windshield and rear window don't phase him?