Conventional car navigation systems seem so... boring. You enter your destination, and it gives you useful, and calmly phrased directions, until you arrive.
Not so the Homicidal Sat Nav from MadCo. It sits quietly, lurking, one might say, on your dashboard, showing a map of an area at least slightly
like the one you are in. From time to time it will direct you, calmly, the wrong way up one way streets, through shopping centres, and into rivers, but this is just its way of teasing you. After a few criminally dangerous mis-directions, you will ignore it happily. It sulks for a few minutes, hours, days, months; who knows, before randomly shouting "Stop!", "turn here", "Look out for the panther", or another unnerving direction. If you end up over the cliff, it smirks - another victim claimed. If not, well there's always another day.
Why - well why not. I suppose I could justify the idea as a security device, but no doubt the lawyers would get you if you killed someone who stole your car, so I won't. I'm tempted to give it at least one useful feature - a 'quickest route' function, for when you need to get from A to B, and don't care if driving down a large flight of stairs or through a restaurant is on that route, but mainly, I just want it to lurk.