Military researchers at DARPA have been looking into how to take the already-fairly-deadly bullet and make it even deadlier by essentially giving it a brain. The Extreme Accuracy Tasked Ordnance, or EXACTO (geddit? Geddit?), is a .50 calibre bullet that has its own onboard guidance systems, enabling it to swerve and change course effectively enough to hit a moving target. It is so accurate, that it even manages to hit its target when an untrained shooter takes a shot. Although this is pretty bad news if you're the one being shot at, the guided bullet is actually intended to save lives by allowing greater accuracy and reducing "collateral" civilian casualties. Other examples of smart bullet technology are able to adjust their flight paths in response to wind and humidity or even detonate explosives on impact. https://www.youtube.com/watch?v=YoOaJclkSZg
