This magic mirror was created for Beauty and the Beast.
It uses an HDMI display controlled by a Raspberry Pi Zero, which responds to two hidden buttons that activate a lightening effect (produced with very bright LED filaments, not EL wire) and one of two video clips required by the play.
The mirror itself started with an actual hand mirror I disassembled, to which I added some EVA foam to make it deeper, and replaced the glass mirror lens with a piece of thin acrylic covered by two sheets of one-way window film.
The back of the mirror was dremel-ed to carve trenches for the LED filaments. After wiring them in and testing, I covered the entire back with clear epoxy and gave it a light mist of gold mirror effects spraypaint, which does a great job of hiding the filaments until they light up.