I had a cat do that to my wife's old solara and I bought this goofy device with a motion sensor that would send out high pitched noise that humans and dogs could not hear. It was supposed to drive the cat crazy. I think it worked, the car quit sitting on top of the convertible.
Do you own a BB Gun? If so a low pump, just enough to hit and scare the crap out of it but not harm it in any way. Or just use a water bottle sprayer. I'm glad I have a garage.