Nanobots including mRNA and graphene hydrogel in COVID vaccine might play the scenario of Grey Goo. Those nanobots have been created by DARPA. They are militarized and weaponized nanobots. They replicate themselves and increase in your body.
70 million atoms of nanobots with power source (lithium) and manipulator arms that can move 1cm per second performing a million atomic pick in place operations. For the fuel, they would be using anything available in your body.
Single nanobot can replicate every 100 second.
How long “death by Grey Goo” will take?
In theory, replicating nano-machines could spiral out of control very quickly.
In their scenario, the end of this world by nanobot vaccine is 20 months later.