Noice.
The U.S. Navy has patents on weird and little understood technology. According to patents filed by the Navy, it is working on a compact fusion reactor that could power cities, an engine that works using “inertial mass reduction,” and a “hybrid aerospace-underwater craft.” Dubbed the “UFO patents, The War Zone has reported that the Navy had to build prototypes of some of the outlandish tech to prove it worked.
Details on the tech/ inventor at the link.