Set in distant future, alright let's jump right to the question... Is it possible to apply nanotechnology to manipulate water molecules to squirt super hot streams of highly pressurized jet of water to slice through a 30mm thick titanium alloy? How will these amphorous water be remote controlled or powered? If they have the ability to multiply quickly in the ocean can we neutralize it afterward or will it cleanse humanity?
My actual design is to condense water vapour inside victim's body thereafter I'll leave some rooms for imagination. Alright I'll give humanity a fighting chance, only use pure water and sand to build your nano-tridents and don't slip up!
Water is essential for life, when there's life there will always be death... toast!