Russia’s Dirty-Bomb Robo-Sub Is ‘Grotesque’—But Moscow’s Building A Base For It, Anyway Five years ago, Russia leaked plans for a bizarre new doomsday weapon. It was unclear whether the nuclear-tipped robo-sub was a real weapon or just a propaganda scheme. Now it seems not only is Poseidon real, it’s a priority for the Kremlin. What’s less clear is why Moscow thinks it's a good idea.