http://en.wikipedia.org/wiki/Grey_goo

www.greygoo.org

www.catb.org/jargon/html/G/gray-goo.html


Grey Goo can only be stopped by creating a new better human-friendly robot to completley wipe out these things that pose a threat to us.
Self-Replication is something that can copy themseleves with using cell divison while cloning involves the joining of cells.