Star Trek prequel
Transcendence could have been a prequel to the Borg race in Star Trek.
The Borg are cybernetically enhanced with -among other things- nanotechnology, and are all interconnected with a collective mind. Their chief goal is to bring about universal peace and physical perfection by "assimilating" all sentient life in the universe, incorporating them into their collective.
The first stage of assimilation is the injection of nanites into the victim's blood stream, which beginning in the 90's was illustrated by a CGI effect of the person's veins turning gray.
Any of this sound familiar?