Cymothoa exigua, popularly known as the tongue-eating louse, is a parasitic isopod that attaches itself to the tongue of its fish host, severs circulation, causing the organ to necrose and fall off, and then becomes the new tongue.
We’ve covered a bunch of terrifying parasites on Oddity Central, but few can hold a candle to the tongue-eating louse in terms of creepiness. This critter is one of the few that actually does the phrase “what nightmares are made of” justice. It enters fish through the gills, attaching to them until it matures, at which point it changes sex from male to female. Once this process is complete, the parasite starts to make its way to the fish’s mouth, where it attaches itself to its tongue using its incredibly powerful legs. It then pierces the host’s tongue with its strong bite and begins to suck the blood out of it. The blood vessels can’t keep up with their appetite, and the tongue eventually withers and detaches from the fish.
