Barry Allen may have a new suit in Season 4 of The Flash but that doesn't necessarily mean that the upgrade comes without an element of danger. In the second episode of the current season, "Mixed Signals," DC Comics loyalists were made aware of various features of the suit, from temperature control to fire suppression to a pulse cannon, but one thing stood out for longtime DC Comics readers, and that was the Babel Protocol.
In the episode, we saw Cisco reveal that he built in the Babel Protocol as a self-destruct mechanism when Flash lost control of the suit, thanks to his battle with the technopath known as Kilg%re. Barry eventually overcame the countdown sequence by striking himself with lightning and regaining control, but what makes this new function such a big easter egg is its nod to the Justice League comics.
JLA: Tower of Babel was a 2000 comic book storyline, from Mark Waid, Howard Porter and Steve Scott, that focused on Ra's al Ghul getting his hands on Batman's secret plans to take out the League members if they ever went rogue. His contingency for Flash was a special bullet that would cause the speedster to seize up, and when the arc was adapted into the Justice League: Doom animated feature, it was retconned where the failsafe was a special bomb attached to Flash.
When asked by Team Flash on the show why he would do such a thing, in true Batman-like fashion, Cisco divulged that it was done because they already faced a dark version of Barry Allen from the future, as seen with Savitar last season, so the genius would rather be safe than sorry in terms of protecting his loved ones. Even if it comes at Barry's expense, Cisco does have a point, but fans will be hoping that this protocol doesn't have to be activated again in the near future, especially with the Thinker looming ahead.
Starring Grant Gustin as the Scarlet Speedster, The Flash airs Tuesdays at 8 pm ET/PT on The CW. The series also stars Jesse L. Martin, Tom Cavanagh, Carlos Valdes, Candice Patton, Danielle Panabaker, Keiynan Lonsdale and more.