When Rex's parents tell her they are adopting a new baby, Rex is afraid she will turn into the Invisible Girl in her own house. Determined to be a good big sister, Rex starts spending all her time with the baby. Now Pinky is afraid that he has lost her friendship. Can Pinky and Rex's friendship survive a cute, warm, and cuddly new baby? Or will Pinky become the Invisible Friend, and have to find someone else to play with? In this sixth book about...