The Regeneration of Penelope Simmons
"Because sometimes, you choose your friends.
Sometimes, your friends choose you.
And sometimes, you accidentally run into a girl with her arms full of cupcakes, and you realize that your idea of friendship was a complete misinterpretation."
In which Penny regenerates with the help of some whacky high schoolers who just might be her friends, leaving her lame, eighth grade, caterpillar self behind for a butterfly of a high schooler.
Or, at the very least, a good ol' moth.