Mirror Mirrors were polished surfaces ( often glass backed with silver , aluminium or mercury ) which cast reflections . Some mirrors exhibited unusual properties . In 1866 , Edward Waterfield and Theodore Maxtible experimented with static electricity and mirrors in an attempt to develop time travel . ( TV : " The Evil of the Daleks " ) Another time machine that used mirrors was developed by General Mariah Learman in the early 21st century . ( AUDIO : " The Time of the Daleks " ) Rhian Salmond had a great aunt who time - travelled through powered mirrors . ( PROSE : " The Book of the Still " ) In a parallel world , UNIT used mirrors and the Doctor ' s TARDIS to create a Lodestone and send Donna Noble back in time . ( TV : " Turn Left " ) Tharil s and Mirrorling s could use mirrors to travel to different dimensions . ( TV : " Warriors ' Gate " , COMIC : " Mirror Image " ) Mirrors were harmful to some life forms ; they were used to defeat the Gorgon on Zeno , ( COMIC : " The Gaze of the Gorgon " ) another Gorgon on Earth , ( TV : " Eye of the Gorgon " ) Medusa in the Land of Fiction ( TV : " The Mind Robber " ) and the Mara on Deva Loka . ( TV : " Kinda " ) The Borad banned mirrors during his reign over Karfel . ( TV : " Timelash " ) The Tenth Doctor punished Daughter of Mine by trapping her in every mirror . She was said to be the strange movement seen out of the corner of the eye when looking in a reflective surface . ( TV : " The Family of Blood " ) The legendary Mortal Mirror of Castle Extremis was a portal to a parallel universe . Those who passed through it and were observed by someone on their side became trapped in the other realm , only able to return to their own reality as fragile beings made entirely out of glass . ( PROSE : " Martha in the Mirror " ) The Fifth Doctor was able to trap the Mara in a Circle of Mirrors , ( TV : " Kinda " ) but the Mara was able to re - possess Tegan and communicated with it via a mirror , being able to as there was no circle . ( TV : " Snakedance " ) The Saturnyn s ' use of perception filter s meant that mirrors would not show their reflections , ( TV : " The Vampires of Venice " ) while the Krafayis could " only " be seen in mirrors . ( TV : " Vincent and the Doctor " ) Susan discovered a full - length mirror in the TARDIS wardrobe which reflected a pale - skinned young man with fangs . ( PROSE : " The Exiles " ) Later , Ace discovered this same mirror and the same reflection of the young man . ( PROSE : " Echo " ) The Second Doctor looked into a mirror to see what he looked like after his regeneration . At first he saw his new face with dark hair and green eyes , but the image wavered and momentarily became the First Doctor ' s . ( TV : " The Power of the Daleks " ) Mirrors were also heavily involved in superstition . Humans , at least , believed that one would get seven years bad luck for breaking a mirror . The Tenth Doctor remarked on this upon realising that he had trapped himself in the past by breaking a mirror serving as a time window , except in his case it was 3000 years since he had come from the 51st century . ( TV : " The Girl in the Fireplace " ) During the Siege of Trenzalore , the Eleventh Doctor used a mirror to freeze a Weeping Angel by forcing it to look at its own reflection , writing " with love from the Doctor ! " on it . ( TV : " The Time of the Doctor " ) The only way Bill Potts was able to see her true cyber - converted self was by using a mirror . ( TV : " The Doctor Falls " )