In a classic The Flash filler episode, Iris learned that she shouldn't hide things from her father (again), Julian worked on his people skills, and Kid Flash — whose headstrong eagerness has become one of the best parts of Season 3 — leveled up in his speedster training. And then there was the now traditional resurgence of Caitlin's inexplicable Killer Frost persona, teasing that the humble doctor is soon to transform into a terrifying villain... until Julian managed to talk her down.
Until Season 3, Caitlin has been one of the most underused characters on The Flash — her role on the team seems to mostly consist of dispensing pseudo-medical advice and giving moral support pep talks. This is rather aggravating, and considering what Caitlin's been through it makes total sense that she would snap and become a villain — but not in the way that #TheFlash is handling her story.
In "Untouchable", Caitlin almost "lost control" when she was using her powers to save Iris' life. But why does using her powers turn her evil, and is it a dead cert that she'll eventually turn into Killer Frost?
A Self Fulfilling Prophecy
At this point, I've pretty much lost all hope that how and why Caitlin using her powers makes her shift into the Killer Frost persona will ever be explained or properly explored. There's no real reason why having meta powers would make Caitlin go evil — unless the show properly explored her character. We've had several allusions to Caitlin's difficult childhood, and it's clear that she's been fiercely repressing her anger for years. She's also lost her husband, and her kidnapping at the hands of Zoom must have been a very traumatic experience.
But instead of these aspects of Caitlin's character being used to explain why having powers makes her want to cut loose and kill things, everything's glossed over in favor of showing us the same scenes over and over again: Caitlin uses her powers, goes a little crazy, gets talked down, represses some more. Rinse and repeat ad infinitum.
There are lots of ways that The Flash Season 3 has been disappointing. The use of Flashpoint was lackluster and rushed, Savitar seems like a weak reboot of Zoom, and the filler episodes feel like reruns from previous seasons. But Killer Frost is a huge plot point, one the show has been teasing from the get-go, and so far Caitlin's villainous transformation feels both over and underwritten.
Hero or Villain?
Just giving us periodic reminders that Caitlin could go bad isn't really enough. We need to know why she wants to lose control as much as why she wants to control herself, we need to understand the root of the conflict within her. We need to care. But just waving the plot point in front of us every so often isn't enough.
I don't know, maybe at this point it's all a self-fulfilling prophecy — the only reason Caitlin's powers are inherently linked to her going bad is because she knows this could happen. To me, that seems like weak storytelling, but with the way Season 3b is playing with ideas of fate and determinism, this could be developed nicely.
I'm not holding out much hope though. But there's no reason why villainy is the only path for Caitlin. As she's proved on several occasions now, her frost powers are a real boon for Team Flash. It would be an interesting twist to see Caitlin overcome whatever mental and emotional problems she's struggling with, to become a superhero instead of a supervillain.
However, what with most of the plot points Barry saw in the future coming true, it looks like Caitlin's transformation into Killer Frost might be a fixed point in time. Personally, I'm okay with Caitlin going full-blown villain, as long as we understand exactly why she snaps. Her development into a superhero would also be interesting.
The worst thing to do with her character would be to just hand-wave the explanations away, have her go nuts and turn into Killer Frost, and then keep her shackled with meta-blockers for the rest of the season, or cure her powers completely. But unfortunately, it looks like this might be exactly what the writers are planning. Here's hoping I'm wrong about that.