Metamorphosis.
Metamorphosis is the process by which some animals change form during their lives, getting closer and closer to complete adulthood. The most well-known metamorphic animal is the butterfly, which transitions from egg to caterpillar (the larva) to chrysalis (the pupa) to butterfly (the adult). Many other animals, such as insects, frogs, crustaceans, and some fishes also undergo metamorphosis.