The second of Doctor Who's 60th anniversary specials, "Wild Blue Yonder," was shrouded in secrecy up until its debut. The episode, which saw David Tennant's Fourteenth Doctor and Catherine Tate's Donna Noble stranded on a spaceship at the very edge of the universe, had been the subject of countless fan theories concerning surprise cameos from past Doctors or famous enemies as part of Doctor Who's 60th anniversary celebrations. However, the truth was that the mystery surrounding "Wild Blue Yonder" was concealing something far simpler and far more terrifying. The episode saw Doctor Who capitalize on Lovecraftian cosmic horror, a genre writer Russell T Davies has notably explored once before on Doctor Who.
Source：https://www.cbr.com/doctor-who-wild-blue-yonder-midnight-cosmic-horror/
