In the new trailer for Fantastic Beasts: The Crimes of Grindelwald revealed at Comic-Con 2018, one key moment finally reveals what Dumbledore sees when he looks into the Mirror of Erised, answering a mystery that has puzzled Harry Potter fans since the first entry in the series, The Sorcerer’s Stone, first published in the UK as The Philosopher's Stone in 1997. If you haven't already, check out the new trailer: In the Sorcerer’s Stone, Harry discovers the Mirror of Erised, a magical mirror that, when looked into, shows the individual what they most desire.