“The title is a Harry Potter reference for all the nerds out there," says Mansoor. "It’s from the first book, in which the Mirror of Erised shows you the things you desire. People apparently waste away looking into this mirror instead of living life. I thought that was a pretty deep concept for a children's book. It’s like a drug.
“The song was a complete accident. My girlfriend always encourages me to play guitar at home, but I don’t feel like playing anything heavy. I just want to play pretty things. So one night I’m playing this pretty trippy thing on the Axe-Fx, with no intention at all of doing anything with it. I had about two minutes of this, and for whatever reason, it really caught the guys’ attention. They loved it. Spencer went to town with it and rearranged it for vocals; he just cut up the demo and put it all together. The chorus is really strong.
“We were on tour with Dream Theater, and we recorded John Petrucci playing a solo on the laptop that plays our backing tracks, samples and MIDI changes. I wasn’t with John when he did it, but when I heard it I was blown away. I was like, ‘Holy shit, we’ve got a Petrucci solo – and it’s incredible!
“John just did his thing. With all of the guest guitarists on the record, we didn’t tell them anything, didn’t make suggestions. We’re just thrilled that they wanted to be on our album.”