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[Flash TV]Why did Caitlin turn into Killer Frost?

I mean, did she have to turn evil? Or is it a side effect of becoming a meta? She was a good person before, and it seems to me that only the scummy people became criminals.
gpt
On 3x05 "Monster" when Caitlin was getting help from her mom, she tested her powers on the hot tungsten metal set to over 2000°C, and she instantly froze it to below freezing temperatures. Then when Caitlin's mom got the results on the screen, she was shocked how she absorbed all that energy or heat. This was a reference to how Killer Frost in the comics absorbs a lot of energy or heat when she uses her powers, she isn't just putting out cold blasts. She's basically an energy vampire the more she uses her powers. Killer Frost absorbing heat or energy causes her emotions to lash out making her become cold blooded with an iced cold heart with lack of empathy for people. Her negative emotions become more predominant with her positive feelings shutdown. 

That's why towards the end of the episode Caitlin's mom warned her not to use her powers. The more she used them, the harder it'll be to reverse. The colder her body becomes which means she absorbing a lot more energy or heat which makes her emotions become more heightened up in anger. The show did not explain this well, but this is a thing for most Killer Frost from the comics, absorbing heat or energy has a catastrophic effect on their psychological state. That's why on the Abra Kadabra episode when Caitlin died and needed her powers to heal that huge wound, she went overdrive and she became full blown Killer Frost with all white hair and pale skin, which meant she was was absorbing a lot more heat/energy and was a lot more angry. Like a switch. She develops a personality disorder like a Jekyll and Hyde situation, or an Incredible Hulk where she has to control her emotions. 

This makes sense she'd develop a personality disorder with her powers, considering all the emotional baggage she went through with losing Ronnie, having her career ruined by the accelerator explosion, the whole twisted fake Jay/Zoom relationship, meeting her E2 doppelganger last year, her terrible mom, and losing her father at a young age. All of that trauma was bound to break lose at some point. She has an origin story for a villain.﻿ That's why on 3x07 or 3x21, when you listen to Killer Frost's quotes, she isn't literally Killer Frost, she's just Caitlin Snow expressing her anger, fears, hate, and pain when she goes nuts. She had emotional outbursts and was trying to get rid of her powers the wrong way before she became full blown Killer Frost.