Its history is unknown, but, apparently, Puck was bound to it, in that it could be used to summon him. The Mirror, eventually, found its way into the collection of the Metropolitan Museum of Art in New York City, where it was placed on display. In 1995, it was stolen by Demona, who used it to summon Puck, intending him to grant her every wish. Of course, being a trickster, he twisted her requests every time. Titania's Mirror was used by Puck as a transport device and focus for his spells. The Mirror temporarily fell into the hands of the Manhattan Clan during the chaos caused by Puck's magical "mistakes", but it was used by Puck to undo his spells, and, after being granted his freedom in return by Goliath, to take himself, Demona and the Mirror itself back to Demona's mansion. Puck then granted an earlier request of Demona -- remaining flesh by day -- but, of course, twisted by him. When she saw her new by-daylight human reflection in Titania's Mirror, she angrily shattered the Mirror. ("The Mirror")
Titania's Mirror had a number of mystical abilities, including the ability to summon Puck, see things far away, and teleport itself and other things. It could also, for unknown reasons, freeze any reflections in its surface in place.
- Titania's Mirror at GargWiki