One of the many scary scenarios of Nanotechnology. Basically it is self-replication gone awry, causing mass destruction on levels we've never seen. You think the bomb is bad (okay, it is :) at least it can be controlled. We've been lucky to escape the Cold War, but will we escape the next one? The scary thing about nanotechnology is that one could destroy the world (no, really, no more life on earth) in a laboratory accident. Nobody, of course, would know about this lab experiment, because it could be done with a few simple tools, unlike the massive amounts of uranium needed for the bomb. At least in the Cold War, we (the US) knew who our enemies were, if nanotechnology is left on the backburners as far as our lawmakers go, we will see a "whole new can o worms."