This is just what I need for self-protection: the "Immobilizer", a stun gun disguised as a cell phone. While sounding very Rambo-ish, it could come in handy with its impressive charge of 900,000 volts. "Take that, Bad Guy!"

Besides, it also doubles as a LED flahlight. It comes with holster, so assuming your assailant is fine with you making a call, you're home free. I'd be worried about setting it off accidentally, but to prevent accidental discharge it has two levels of safety.