There isn't a single book called "Terrible Two". It's a common phrase used to describe a stage of toddler development, often associated with tantrums, defiance, and a general sense of "terrible-ness".
Perhaps you're thinking of a specific book about toddlers or a book featuring a character who embodies the "terrible two" persona? If you can give me more information about the book you're thinking of, I can help you find the main character!