‘The Flash’ has given us one of the best ensemble casts in all of genre television. Caitlin Snow was introduced as a brilliant scientist and series regular, especially with her cold attitude, it was a given that one day she’d become Killer Frost. We even got a preview at the end of the first season, but that just turned out to be Earth-2 Caitlin Snow. Nevertheless, it’s very likely we’ll get the Earth-1 component; with all the tragedy Caitlin’s been through, it’d be a natural course for her character. But the question is, just how could it happen?