The Yellow Jacket is the thing you probably didn’t know you needed (and maybe still don’t need but would like to see a video of): a combination iPhone case and stun gun. Put in your iPhone 4 or 4S–and, soon, iPhone 5–then power up the case and send some voltage to the bad person nearby. Also, less uniquely but still helpfully, the case acts as a battery charger, juicing up your phone while you defend yourself from a mugging or whatever. It even comes in a variety of colors so you can express yourself during said situation.
CES 2014: Finally, An iPhone Stun Gun [Video]