This totally reminds me of something James Bond or the new Batman would use. Basically it's a knife that injects a cold ball of compressed gas at approximately 800 psi…instantly. For those of you who aren't aware, if you decend underwater to a significant depth and then ascend back to the surface quickly, your lungs could rupture due to the unbalance of air pressure inside and outside of your body. That is essentially principle behind the WASP. The site has a video demonstrating its effects on a watermelon which looks potentially devastating if used on an actual predator, man or animal.