Four decades into their career, Green Day certainly haven't lost energy. That was certain the case on their pumped-up performance of "Bang Bang" on Fallon last night.

Bille Joe Armstrong and his crew of punk rockers were as fiery as ever performing the intense, political song written from the perspective of a mass shooter. 

"It's about the culture of mass shooting that happens in America mixed with narcissistic social media," explained Armstrong to Rolling Stone. "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. To get into the brain of someone like that was freaky." 

"Bang Bang" is the lead single from Green Day's twelfth studio record Revolution Radio, which was released today (October 7).