A mysterious entity referenced only once in the series at the conclusion of Ten's plot arc. As The Doctor begins to regenerate, he mentions that he doesn't want "Tuggo". This ominous reference has left many Doctor Who fans bewildered and produced intense speculation for years, since the "Tuggo" plot was referenced in The Doctor Falls by the 12th doctor. He doesn't want "Tuggo" either. Something's up with timelords and their tuggo.