Problem is, there aren't many mammals with 3 claws in front... the one that comes to mind is the 3 toed sloth. So... either a sloth scratched your car, or it's an anisodactyl bird that scratched you - like an eagle or hawk that would otherwise hunt and eat cats, and not the other way around (for the most part). Of course, those of our friends from the bottom of the world may mention the kangaroo... but if you're getting scratched by the hind legs of a kangaroo it looks more like a Raptor attacked you with its 1 long claw than 3 evenly gaping wounds.
FWIW - it isn't the Monster claw.