The WASP knife as it is named looks as simple as a ordinary knife but is more harmful that earlier. It has 24 grams of compressed gas in its slender body. When ever something hits it the gas in the knife enters into the wound at 800 PSI. And the gas can enter the wound even if it is under water making the victim enter into a whole new world of hurt. Apparently, this dangerous knife is sold strictly to the non-civilian market, but you never know just how a careless moment could cause this to leak out for those with more wicked purposes. The WASP knife retails for $389.