As the cercaria penetrates the skin it transforms into a migrating schistosomulum stage.
From the en.wikipedia.org
Penetration of the human skin occurs after the cercaria have attached to and explored the skin.
From the en.wikipedia.org
This free-swimming stage of a parasite larva, a trematode cercaria, leaves an infected snail to encyst on a fish brain.
From the sciencedaily.com
More examples
Tadpole-shaped parasitic larva of a trematode worm; tail disappears in adult stage
(cercarial) of or relating to cercaria
A miracidium is a small free-living larval stage of parasitic flatworms in the class Trematoda. It is released from eggs which are usually shed in the faeces of its vertebrate host. ...
(cercarium) an infectious form of Schistosoma which infects their hosts by direct skin penetration; cercariae emerge daily from the snail host; they are highly motile, alternating between vigorous upward movement and sinking; cercarium attaches to the human skin and secretes proteolytic enzymes ...
State of development of certain parasites enabling them to enter the human organism.
Free-living, tailed larval stage of trematodes; may infect humans by direct penetration (schistosomes); may attach to vegetation and encyst to metacercarial stage (Fasciola, Fasciolopsis), or may penetrate tissues of vertebrates or invertebrates and encyst to metacercarial stage (Clonorchis)).