"A Dryad Mam." You politely state, hoping and wishing it was true. Without saying any thing you feel the transformation happen. Your hair and eyes turn ultra-green. Your skin turns into some kind of smooth and flexible bark. Then, things take a turn, you feel weight added to your chest and a strange feeling... down there. Finally able to move again, you see that your clothes have fallen to the floor, ripped to shreds. "What about clothes?" you ask. "Oh, you won't be needing them, not in this academy," the headmaster states. Then, feeling about your new body you again ask "Why am I now a girl?" "That's my bad, I only am able to transform female dryads." She says, a bit embarrassed.
[Author: I didn't have much time to make this but main character is now a female dryad. She can control plants and morph into them. Please keep the thread in this pattern.]