Max Adler
“Glee” alum Max Adler will play an obsessive music fanatic who loves to set things on fire in an upcoming Season 4 episode of “The Flash.” Pictured: Adler arrives at the premiere of Sony Pictures Classics’ “Midnight In Paris” at Academy of Motion Picture Arts and Sciences’ Samuel Goldwyn Theater on May 18, 2011 in Beverly Hills, California. Getty Images/Frazer Harrison

Max Adler’s guest-starring role in Season 4 of “The Flash” has been revealed.

According to FlashTVNews, Adler will play the role of Jaco Birch, “an obsessive music fanatic who worships at the altar of classic heavy metal.” He’s also a roadie for unknown contemporary metal bands and loves to set things on fire.

Adler’s upcoming appearance on the CW series was first revealed when he was spotted filming scenes with series star Candice Patton at Harbour Green Park in downtown Vancouver last week. According to Canadagraphs, Adler and Patton were filming scenes for Season 4, episode 16 at the time. The said installment will air sometime in March.

Adler rose to prominence for his role as Dave Karofsky on the Fox musical dramedy “Glee.” The 32-year-old actor also played the characters of Miles “Tank” Conroy on ABC Family’s “Switched at Birth,” and Jesse Smith on CBS’ “The Young and the Restless.” On the film side, Adler appeared in the 2013 Liam Hemsworth starrer “Love and Honor” and in the 2016 biopic “Sully,” starring Tom Hanks in the lead role.

Meanwhile, in this week’s Season 4, episode 12, Cisco (Carlos Valdes) and Ralph (Hartley Sawyer) are shrunk to miniature versions of themselves after getting caught in the crossfire of a meta-human who can shrink anything he touches.

The meta-human is played by Derek Mears, who is best known for his role as Jason Voorhees in the reboot of “Friday the 13th” and Hawes in “Hatchet III.” A quick look at the actor’s IMDb page reveals that his “The Flash” character is named Sylbert Rundin, aka Dwarfstar.

In the comics, Sylbert was a student and serial killer who stalked the dormitories of Ivy University. He acquired a Bio-Belt which gave him the ability to shrink his body down to the atomic level.

In the trailer for the episode, Sylbert doesn’t seem to have a Bio-Belt. But he has a gun-like weapon that seemingly has the powers to shrink anything or anyone.

Elsewhere in the episode, Cecile (Danielle Nicolet) realizes her pregnancy has caused her to have temporary powers and discovers that she can hear other people’s thoughts.

“The Flash” Season 4, episode 12, titled “Honey, I Shrunk Team Flash,” airs tonight at 8 p.m. EST on The CW.