The Dark Knight features a surprise cameo from the singer and guitarist of Blink-182 and Alkaline Trio. Released in the summer of 2008, Christopher Nolan's second Batman effort proved to be a defining moment in modern cinema, giving the superhero world Heath Ledger's magnificent portrayal of Joker and mastering the gritty, urban styling introduced previously in Batman Begins. One of The Dark Knight's biggest side stories is the threat of Bruce Wayne's secret hobby being revealed to the public, after a Wayne Enterprises employee finally puts two-and-two together and figures that Lucius Fox's R&D department is finding its way onto Gotham's streets each night.
Matt Skiba first came to prominence as the frontman of Chicago-based punk band Alkaline Trio, who have released genre classics such as From Here To Infirmary, Good Mourning and Crimson while touring globally since the 1990s. While Alkaline Trio are widely considered punk-rock royalty, they never quite broke the mainstream in the way some of their contemporaries did, but after Blink's Tom DeLonge left the band to investigate the existence of alien life (seriously), the remaining band members drafted in Skiba as a replacement. In 2019, Skiba juggles both bands simultaneously, but the musician has also enjoyed a very brief movie career.
In The Dark Knight, Coleman Reese announces to the world that he knows the identity of the Batman and Joker is none too happy with the pen-pusher threatening to spoil his fun. Ledger's villain tells Gotham that he'll blow up the city's hospital unless Reese is assassinated, motivating a wave of angry, anxious citizens to hunt down the Wayne Enterprises employee. For his own safety, the GCPD attempt to move Reese from the Gotham City news studio he plans to make the announcement on and, as the entourage passes the building's front doors, an angry mob calling for Reese's head is waiting outside. One of the most prominent faces among this throng is Alkaline Trio's Matt Skiba.
In the years since, the legitimacy of this cameo has been confirmed, but is quite a departure for a film trilogy that generally doesn't partake in the joviality of fan-pleasing cameos. The grounded, serious tone of The Dark Knight trilogy doesn't lend itself naturally to fun guest appearances in the same way that the MCU did for Stan Lee cameos. Fortunately, Skiba enjoys a level of fame where he can still do the grocery shopping without being accosted by a horde of followers, and his appearance in The Dark Knight would go unnoticed by anyone who isn't already a fan of his band. Since joining Blink-182, of course, Skiba's public profile has increased significantly.
While Batman and pop-punk maybe aren't natural bedfellows, Skiba's cameo isn't as surprising as it might first seem. Filming for The Dark Knight primarily took place in Skiba's home city of Chicago and the man himself is a fan of the character. More speculatively, Alkaline Trio began releasing records through the Epitaph record label around the time of The Dark Knight. Epitaph are distributed by Warner Bros., the studio behind DC's movie output, so there might've been a potential in-road there, perhaps even just to find out how to get on the extras list.
