Nanotechnology can be as deadly as any other kind of weapon. While it’s a great instrument in terms of healing, growing body parts, organs, and whatnot, nanobots can also be used to wipe out whole cities as there would be literally no cure that would stop this ‘plague of locusts’. One mistake is all it takes to transform the ultimate weapon into a means of world destruction. Self-replicating nanobots are virtually indestructible – they can’t be bombed, shot at, or captured. If they get out of hand – the whole world is doomed.