Fish Parasite

4.3 centimeters crustacean enters the body through the gills of fish and fish bites into the tongue. Over time, the tongue dies out due to lack of blood, and parasite replaces it with his body. Fish can use the parasite as a common tongue, and apparently no harm, except for loss of tongue, of the parasite do not. This is the only known case in which the parasite replaces the body with all its features.