A transmutation is a change that might not be apparent on the surface. By contrast, a metamorphosis is a complete change in form or substance. Depending on the circumstances, possible synonyms for “metamorphosis” include “reinvention” and “rebirth.”

Example:  “Children are always amazed at the process of metamorphosis that changes a lumpy leaf-chewing caterpillar into a delicate, nectar-sipping butterfly.”