[Photo by: Brendan Walter]

Fall Out Boy have shared an unreleased song from their latest album M A N I A in the best way possible.

Read more: Joe Trohman won’t be joining Fall Out Boy on UK tour

London fans were sent on a FOB scavenger hunt when a video of Pete Wentz hiding a T-shirt under a traffic cone surfaced on the band's Twitter.

The band hid three shirts in total near the O2 Arena, all of which were teased on the band's social media accounts, causing fans to go into a frenzy as they frantically searched for the exclusive merch.

But a really snazzy T-shirt wasn't the only thing they got.

An unmarked USB drive accompanied the shirts which contained a previously unreleased demo of “Young & Menace.”

Lucky for us, one of the fans uploaded the song to YouTube for all FOB fans to enjoy.

Check out the piano version of “Young & Menace” below!

What do you think of this previously unreleased FOB track? Let us know your thoughts in the comments below!