metacercaria
/ˌmɛtəsəːˈkɛːrɪə/Zoology
noun
The encysted final larval form of a trematode (parasitic worm), into which a cercaria develops prior to assuming the adult form in the definitive host.
Origin
1920s; earliest use found in American Naturalist. From meta- + Cercaria, after French métacercaire.