Rose Tyler (Doctor Who)
While they are travelling, the Doctor and Rose realise that the words "Bad Wolf" follow them around. They discover that Rose herself is the Bad Wolf, and that the words are a message. They tell Rose that she must travel to the future to absorb the energies of the time vortex, to save the Doctor and the Earth from the Daleks.  By absorbing the power of the TARDIS, she destroy the Daleks, brings Captain Jack back to life and leaves the words "Bad Wolf" through the universe as clues that are seen throughout the series.