Meet CRACUNS, or the “Corrosion Resistant Aerial Covert Unmanned Nautical System.” It’s a submersible drone, made by the Johns Hopkins Applied Physics Laboratory, designed to straddle the littoral space between unmanned aircraft and unmanned underwater vessels. It is also made for the littoral, that part of the ocean between the beach and the high sea. Parts of it are 3D printed, to create a watertight body, and other parts are coated in commercial sealant, to keep the water out from the engines. According to Johns Hopkins, its “low cost makes it expendable”, though given that the customer is the Pentagon, “low cost” isn’t that revealing a metric.