The provocative new song is penned from the perspective of a killer, and features lyrics like, "You're dead, I'm well-fed/Give me death or give me h**d."
Billie Joe reveals he wanted to explore the mindset of a murderous gunman to make a statement about the current state of affairs in the U.S., where mass shootings have been on the rise.
He tells RollingStone.com, "It's about the culture of mass shooting that happens in America mixed with narcissistic social media. There's this sort of rage happening, but it's also now being filmed and we all have ourselves under surveillance. To me, that is so twisted."
Armstrong admits writing the track gave him chills.
"To get into the brain of someone like that was freaky. It freaked me out," he confesses. "After I wrote it, all I wanted to do was get that out of my brain because it just freaked me out."
"I don't know why someone would ever do something that horrific because I know I never would," Armstrong added.
Bang Bang is the first single from Green Day's new studio album, Revolution Radio, the follow-up to 2012's Tre!, which is set for release in October (16).