Ryuko was so tired how satsuki bosses around in the Honnouji Academy, so she challenges satsuki to a fight. Satsuki accepts her challenge, but she didn’t know what ryuko actually had under her sleeves. Ryuko actually wanted to try a vial that can shrink opponents, she wanted to show satsuki who’s the boss here.
Ryuko: Kiryuin Satsuki! I’m freaking tired of you bossing around, and just sitting there doing nothing. I challenge you and will show you who’s the boss here.
Satsuki: ha, Matoi I accept your challenge, I will crush you and defeat you instantly.
Ryuko: take this!
Ryuko throws the vial at satsuki. Splat! The vial gets all over her and she starts to feel weird and a little dizzy.
Satsuki: what the hell? What is this?
Ryuko: you will see
Satsuki begins to shrink
Satsuki: what! I shrunk
Ryuko: not so bossy now kiryuin right, now I’m in charge, I demand you to worship my feet or else I will step on you and crush you
Satsuki didn’t had no choice but to listen to her since she’s tiny and vulnerable
Satsuki: as you wish lady Matoi
Ryuko: I like you better this way, you under my charge