Elongated Journey Into Night

"Elongated Journey Into Night" is the fourth episode of the fourth season of The Flash, and the seventy-third episode overall. It aired on October 31, 2017.

Synopsis
Cisco is shocked when Gypsy's father, Breacher, shows up on Earth-1. Breacher takes an immediate disliking to Cisco and decides to hunt him. Meanwhile, Barry runs into his old nemesis, Ralph Dibny.

Trivia

 * Cisco refers to Breacher as "the Predator" and himself as "the Schwarzenegger", referencing Arnold Schwarzenegger's role in the 1987 film Predator.
 * Ralph Dibny claims to look like "a Hemsworth", referencing actors Chris and Liam Hemsworth, who are known for their muscular appearances.
 * A poster for the movie "The Matrix", can be seen on Cisco's bedroom wall at the beginning of the episode.
 * According to the IOU card photo Ralph left, which is dated October 10, 2017, which Barry states is the same day he came out of the Speed Force in "The Flash Reborn", however since "Finish Line" takes place on May 24, 2017, and "The Flash Reborn" takes place 6 months after the events of "Finish Line", that would place the events of "The Flash Reborn" sometime around November 24, 2017.
 * When Barry and Iris are investigating  Ralph Dibny's office, Iris opens a drawer and a bottle of Gingold is shown to be inside the drawer. In the comics, "Gingold" is the drink that gives Dibny his elastic powers.
 * Ralph Dibny was previously mentioned as a victim of the particle accelerator explosion at S.T.A.R. Labs. As a result of Flashpoint, he is now alive.
 * This is the first episode of Season 4 that Neil Sandilands doesn't appear as DeVoe.
 * Barry drops the name Plastic Man, which is a reference to the DC Hero with similar powers as Ralph Dibney.