A wrist mounted gun that shoots rapid fire darts. That, or a wrist mounted pole that, when you role your hand down to avoid getting hit, you hit a button and launch a 4" to 2 foot (Arm fully extended adds an additional portion to the pole. Thought it out!) sharpened metal pole at your enemy. I just like the idea of being two feet away in the shadows, hit a solider in the back of the head with this sharp pole laced with poison, he goes into conniptions, and you sneak past while everyone is distracted by Ted and his seemingly not related to spy activity seizures. That would only work on untrained personal, but it would still look cool. Or, you get caught by one guy, he cuffs you behind your back, you aim a bit and bam! Hit with a wrist mounted spear. Take the keys, let yourself out of the cuffs, and leave. It would be like a hidden katar, but can be used as a rapid firing mechanism; three unarmed men approach you, and you fire the thing like a tentacle and kill them. Get two of those and your set. Also, not like the blade in Assassin's Creed. That was a small blade used for close quarters assassinations. I'm talking about what is basically a inflexible metal tendril.