The Johns Hopkins University Applied Physics Lab has developed a drone that can operate effectively either underwater or in the air. The Corrosion Resistant Aerial Covert Unmanned Nautical System, or CRACUNS, was designed and 3D printed to be lightweight, waterproof, and inexpensive; it's capable of lurking underwater for up to two months without any damage. Once released, the CRACUNS can rise from a depth of hundreds of feet to launch itself off the surface of the water and into the air. While specific uses have not been given, it's expected that the drone will lend itself to a wide variety of naval missions. Read more at 3DPrint.com: http://3dprint.com/125251/cracuns-3d-printed-drone/