Mother Bird accuses Alice of being a serpent after Alice grows to a super large size and her head crashes up into the mother bird's nest. Alice thinks quickly and eats another piece of mushroom and shrinks down just as Mother Bird is collecting her eggs from the nest and flys them to safety.
From the book:
As there seemed to be no chance of getting her hands up to her head, she tried to get her head down to them, and was delighted to find that her neck would bend about easily in any direction, like a serpent. She had just succeeded in curving it down into a graceful zigzag, and was going to dive in among the leaves, which she found to be nothing but the tops of the trees under which she had been wandering, when a sharp hiss made her draw back in a hurry: a large pigeon had flown into her face, and was beating her violently with its wings.
`Serpent!' screamed the Pigeon.
`I'm NOT a serpent!' said Alice indignantly. `Let me alone!'
