Cause and Effect

"Cause and Effect" is the twenty-first episode of the third season of The Flash, and the sixty-seventh episode overall. It aired on May 9, 2017.

Synopsis
Barry takes drastic measures to stop Savitar. Meanwhile, H.R. continues to push Tracy Brand to design the trap for Savitar, and Killer Frost returns with an interesting proposal.

Trivia

 * Cisco mentions the Star Trek: The Original Series episode "The Enemy Within" in which Captain Kirk is split into good and bad personalities.
 * H.R. mentions having Star Trek: Voyager on his Earth, to which Cisco claims to hate spin-offs. This is likely a tongue-in-cheek joke, considering the fact that The Flash is a spinoff of Arrow.
 * According to Barry's driver's license, it says that he renewed it on March 10, 2014. However, Barry was in a coma from the time of December 11, 2013 to September 2014, meaning he couldn't have renewed it during this time, assuming that it has to be renewed in person (unless a military member or dependent) like in real-life Missouri that Central City is placed in.
 * After losing his memories, Barry asks to be called "Bart", a reference to to Bart Allen, who is Barry and Iris' grandson in the comics.*Barry is revealed to have been a huge fan of anime in high school, with Iris mentioning that Dragon Ball Z was one of his favorites.
 * Coincidentally, this episode aired on the Japanese-recognized holiday "Goku Day".


 * Rather than "the Flash", Barry suggests that they call him "the Streak", a moniker used by Clark Kent on Smallville.
 * The Flash was also called the Streak during Season 1


 * Tracy states they require 38.6 terajoules (38,600,000,000,000) of energy to trap Savitar, and Cicso claims this is more than the energy of the Sun; this is vastly inaccurate, as the Sun releases 384.6 yottajoules (384,600,000,000,000,000,000,000,000) of energy every second.