The Body Changers(2000)

For humans, change, mutation, is part of the very process of life, from birth to death. But for some living beings, change is far more radical. Tadpoles transform into frogs, caterpillars into butterflies, and these aren't even among the most radical changes possible in nature. The ability to transform, to change, is often crucial for survival. Only by adapting to their surrounding environment, through extraordinary transformations, can these animals continue to live on our planet.