Cymothoa exigua
Cymothoa exigua, or the tongue-eating louse, is a parasitic isopod of the family Cymothoidae. It enters fish through the gills and the female attaches to the tongue, with the male attaching on the gill arches beneath and behind the female. The parasite severs the blood vessels in the fish’s tongue, causing the tongue to fall off. It then attaches itself to the remaining stub of the tongue and becomes the fish’s new tongue.
This is the only known case of a parasite assumed to be functionally replacing a host organ.
A mutated version of Cymothoa exigua was explored in the eco-terror film The Bay.
The-insiders-©-Qing-Lin-Wildlife-Photographer-of-the-Year
Apparent death
Paralysis
Pinch-induced behavioral inhibition