https://www.themoscowtimes.com/2020/...testing-a70386
Yup, its a unmanned nuke torpedo, one of thousands to be made. 10,000 kilometer range torpedo that hugs the seafloor and is much much stealthier than anything in the air. Arguably impossible to track with any known technology.
Sure, its slow but that's the goal. If you attack Russia, two weeks the AI drone brain will find its way to the coast of whatever country started it. Ultimate deterrent is not based on speed, first strike is based on speed.