Understanding 'Transformation' in Context

During a school project, Clara was tasked with presenting the life cycle of a butterfly. As she gathered information, she became fascinated by the transformation that these creatures undergo, from caterpillar to chrysalis to butterfly. To her, the process was not just about change, but also about growth. Her classmates were eager to learn about this captivating journey.

What does the word 'transformation' mean in this context?