Supergirl is impervious to a lot – but not, apparently, to a leech-like alien parasite that floods her with false memories while she’s trapped in a comatose-like dream state. And in Kara’s case, her personal dream world, informed by her deepest desires, puts her back on her home planet of Krypton, where she’s hanging out with her little cousin – Kal-el, better known in his older and flashier iteration as Superman.