Pretty sure I've posted this here before, but a kid I went to High School with had a Plymouth K Car. He used to "modify" things on it all the time to fit certain situations...low budget James Bond kinda shit.
He installed a spare washer fluid tank and motor (courtesy junkyard). He filled the tank with black ink. He ran the hoses back to the trunk (all tucked in or under the car or something so you couldn't see them). He aimed them at the right height and position so that when someone was tailgating him, he hit that squirter and threw black ink all over their windshield. Well of course someone's first instinct is to hit their wipers, which would smear the ink, and make it even worse. That would stop the tailgaters quickly. This is illegal btw.
He installed a paintball gun behind the grill. Hit a switch, grill falls open and he had a trigger for the paintball gun at his controls by the steering wheel.
All lights were on toggles. If he wanted (or needed) to have his taillights and/or brake lights OFF while having his headlights ON, just flip the switch.
This guy was doing something different to that car every couple weeks. Funny dude too. Absolutely crazy guy.