From the very beginning, those familiar with comic book lore knew that Caitlin Snow would become Killer Frost at some point on The Flash, with the big moment arriving in season 3. Well, actually, we did meet Earth-2’s version during season 2, but that’s a different story altogether.
As fate would have it, Earth-1’s iteration ultimately became a force for good, thus being somewhat similar to her literary counterpart in recent years. Unfortunately, though, the Thinker seemingly snuffed out the Killer Frost alter ego late in season 4, forcing us to believe that only Caitlin remained.
Oddly enough, Ms. Snow experienced flashbacks to her childhood proving that her Killer Frost side predated the particle accelerator explosion, therefore her powers were not the result of exposure to dark matter. Luckily, we got the true answer to the riddle during “The Icicle Cometh” just last night.
You see, when Caitlin finally discovered the whereabouts of her father, Thomas, who’d previously been thought dead, he revealed how he suffered from ALS years before. And to counteract the affliction, he used experimental cryogenic methods – but a new disease altogether emerged in its place.
In a cruel twist, Caitlin was found to bear the genetic marker for ALS herself. Because of this, Thomas used similar methods on her, with the side effect causing the Killer Frost dual personality to manifest.
Thanks to Cisco’s genius, it was figured out that Thomas also had an alter ego of his own, that being the Icicle. The downside, however, is that he has almost complete control of Thomas’ brain, so it may be some time before Caitlin truly gets her father back. On the flip side, fans of the series just gained yet another great villain, so let’s just sit back and enjoy seeing how this all plays out.
The Flash airs on Tuesday nights on The CW.