Via NBC News, the Navy is working on making the bottom of the sea less peaceful:
The U.S. Navy wants to pack aerial drones and other intelligence-gathering technology into special containers built to withstand deep ocean pressures and distribute them around the world’s seas. The containers will rise to the surface when called into service from a remote location.
These “upward falling payloads” are seen as readying the Navy to address conflicts in corners of the world where it is too expensive or complex to establish a forward operating area, the Defense Advanced Research Projects Agency (DARPA) explained in a call for proposals.
The containers would be stealthily deployed well ahead of time and designed to stay put on the seafloor for years.