After Fred's death, George was wandering through Hogwarts, wondering how much damage the school had suffered.
He entered an unused classroom, and came across a beautifully engraved mirror. Carved into it were the words "Erised stra ehru oyt ube cafru oyt on wohsi".
He peered into the mirror, but saw only his own reflection. With a shrug, he left the room, wiping a tear from his eye.
What he didn't notice, was that the George in the mirror had both ears.