"There’s a lot of scared people with this monster running around the city."
Iris West
"Monster" is the fifth episode of the third season of The Flash, and the fifty-first episode overall. It aired on November 1, 2016.


Desperate to understand what is happening to her, Caitlin visits her mother, Dr. Tannhauser, a renowned biomedical researcher, in the hopes that her mother can provide some answers about Caitlin's growing meta-human powers. However, when Dr. Tannhauser treats her daughter like a test subject, Caitlin grows cold and brings up past wounds causing the two to have a major blowout. Meanwhile, after a mysterious new meta-human attacks Central City, Barry tries to convince Julian to let him assist on the case.[1]


Eddie Thawne's photograph on the wall of SCPD

Eddie Thawne's photograph is in the upper right corner.

  • A photograph of Eddie Thawne can be seen on the wall at CCPD.
  • H.R. asks Team Flash, "Has there been none amongst you that has ever shaded the truth for what you believe to be the greater good?". "Shade" is the title of the next episode of The Flash.
  • Cisco makes yet another Star Wars reference in this episode, but H.R. does not catch on. This is the same reference made by Spider-Man in Captain America: Civil War.




  1. The Flash Spoilers: “Monster” Description – We Meet Caitlin’s Mom! - FlashTVNews