Mrs. Whatsit is a character from the novel "A Wrinkle in Time" by Madeleine L'Engle. She is a mysterious being who can transform her appearance and is known for her whimsical and playful nature. Mrs. Whatsit helps the main characters, Meg Murry and Charles Wallace, on their journey through space and time. As a member of the celestial beings known as the Mrs. Whatsit, Mrs. Who, and Mrs. Which, she embodies the theme of love and courage. Her character represents the idea that even the smallest actions can have a significant impact in the fight against darkness.