Nowadays we don't have any direct understanding of myth, but we can understand it somewhat through the context of history.
Here we see Carrie play the role of the "Greek chorus". Although it is only one actor (traditionally a Greek chorus consists of two or more actors outside the action), the role of this narration is to provide context to the story and give an idea of what is about to happen.
In our modern Socratic society we shun art and drama in favour of the pursuit of knowledge.
Nietzsche would be so proud, as he believed that to save modern culture from self-destruction we had to bring back the spirit of tragedy. Dead frogs...
...lack of school supplies...
...failing a class due to your moral beliefs about dissecting frogs.
A classic Dionysian response, giving free rein to ones impulses, passions and emotions.