metamorphosis

METAMORPHOSIS noun

uk/ˌmetəˈmɔːfəsɪs/ usplural metamorphoses uk/metəˈmɔːfəsiːz/ metamorphosis noun
(GROWTH)

in biology, the process by which the young forms of some animals, such as insects, develop into very different adult forms

метаморфоз
Caterpillars changing into butterflies is an example of metamorphosis .