On tonight's The Flash, the investigation into who Cicada is continued as did the quest for answers about Caitlin's father which led to a shocking revelation about the true origin of Killer Frost.
Spoilers for tonight's episode of The Flash, "The Icicle Cometh," below.
While everyone else went out in pursuit of clues to help lead Team Flash to Cicada, Caitlin (Danielle Panabaker,) Cisco (Carlos Valdes,) and Barry (Grant Gustin) located the safehouse where Caitlin's father Thomas Snow (Kyle Secor) has been for years. It turns out that Thomas had ALS and experimented on himself with cryogenics to cure it. He was successful, but after collapsing while on a walk he reveals that he gave himself another disease in the process.
Caitlin, while treating him, figures out that her father also experimented on her as a child. It turns out that Caitlin also had the genetic markers for ALS and, to save her, Thomas did a similar procedure on her to stop the disease from ever manifesting and, in the process, created the second personality now known as Killer Frost.
This new information confirms what Caitlin and Cisco discovered last season when they found, via Cisco's vibe powers, that Killer Frost existed within Caitlin when she was a child -- long before the particle accelerator explosion that unleashed dark matter and created The Flash and the other metahumans during Season 1. The information changed everything for Caitlin, especially since an encounter with The Thinker seemed remove her ability to access her frosty side. It’s information that Panabaker herself has said is very important for Caitlin.
"I think it's going to be really important," Panabaker told ComicBook.com of Caitlin figuring out her past. "You know, toward the end of the season we saw Caitlin try to understand a little bit more of why she disappeared... so I think also this year she's uncovering some mysteries about Killer Frost and how Killer Frost came to be and we're going to see her delve into that."
Knowing that Killer Frost is unquestionably part of her opens the door for Caitlin to find a way to bring her alter ego back. It also raises some serious questions about what's going on with her father -- and what that might mean for not just Caitlin, but Team Flash on the whole.
What did you think about Killer Frost's origin on The Flash? Let us know in the comments.