Mirror Mimicry – The character is a mirror.
The Magic Mirror is an example of this state of being and can answer most questions but not all questions (Fables V1 #19).
Martyn who is the last member of the Cult of Cold Flame doesn’t like what his mirror advises and reacts violently (The Books of Magic V2 #6).
The DC Silver Age liked to turn superheroes into mirrors or characters with mirror like qualities (World’s Finest V1 #121, Flash V1 #126, Justice League of American V1 #7).
There are many mirrors in Trading Card Games.
Mirror of Erised
Mirror of Lacef