The Singularity
The singularity is the term used to describe the hypothesised moment when technology becomes so advanced it radically changes civilization as we know it. This could be from an artificial intelligence reaching a level of super intelligence we cannot imagine, human biology and technology becoming so intertwined that we become almost part machine, or even if we achieve the ability to upload our consciousness so that we essentially live forever.
The danger of the singularity comes from the risk that we may stop being human altogether. Could there come a point in the far-flung future where technology really does advance to such a point that we cannot imagine the consequences? Or is it just something in the fevered dreams of technophobes?