I'm thinking of some sort of point-blank nanoweapon, one in each of the fist. 

My original idea was a small flamethrower on each knuckle, with a trigger also on the knuckle, so when someone punches another person, it burns the flesh. If it's handmade, say the base is a winter glove, if not use a shiny metal gauntlet. I'm a Sci-Fi person, so I'm going to be going into the advanced tech. 

First of all, I thought of a small needle that punctures the skin then draws tissue, which triggers the mechanism. This would look like a thin ring with a needle on it and a wire leading down the arm. The whole thing would be hidden by a long sleeve. The actual weapon would do two things: 

- open a valve which releases a vaporized sticky napalm, preferable early on in the fight or before it even starts. 

- The second part is triggered by the needle, which is essentially the sparking of a lighter. 

The result: A sly way to BURN YOUR ENEMIES TO DEATH!