What a fucking asshole! I'd be tempted to just ram his ass and his precious douchebaggery Prius.
These days I would have done whatever it took to get away from him up to & including jumping off an exit behind him & stopping for 2-3 minutes.
However back in the days when I was a courier (also young & crazy) I would literally have run him off the road.
People need to think before doing stuff like this especially when driving a tiny dog-slow car.
Edit: And in my experience this guy is the exception ... Prius drivers tend to be annoying & slow but far from aggressive.