The second verse and the chorus are sung by Skylar Grey. Regarding how the Grey collaboration came about, Shaddix told the Q103 radio station:
"We wanted to have a guest female vocal on ['Periscope'], and on the last album, we had Maria Brink from In This Moment on 'Gravity
'. I didn't wanna just go in and grab another rock chick. I wanted to work with somebody that was outside the box and different but that I was a fan of. So I've been listening to this girl Skylar Grey for [a few] years now. And she's been on some great tracks — she's been on some Dre stuff
, some Eminem stuff
, she's been on a Fort Minor
track. But she's kind of this indie, alternative, pop type of girl, and she's just got a lot of credibility in that scene, and she's got a great voice, and I'm a big fan."