A parasite that eats the tongue of the host and replaces it is the sort of creature straight out of nightmares, more at home in science fiction or a horror movie than the real world.
Unfortunately, this tongue eating parasite is very much real, though the fact that it can't get at humans is a comforting thought.
The horrific creature was revealed in a Facebook post from Galveston Island State Park in Texas which showed a picture of a very unfortunate Atlantic Croaker with one of the parasites firmly embedded in its mouth.
'MARTIAN SPOTTED AT GALVESTON ISLAND STATE PARK', the post read, before continuing with, 'Ok, so not really... but this is still pretty spooky!'
The post named the horrifying parasite as a 'tongue-eating louse', a parasitic isopod.
'This parasite detaches the fish's tongue, attaches itself to the fish's mouth, and becomes its tongue.' The wildlife agency wrote, explaining in detail the gruesome process shown in the picture, 'The parasite then feeds on the fish's mucus. It also happens to be the only known case where a parasite functionally replaces a host's organ.'
As if cutting off their tongue and replacing it wasn't bad enough, some of the nastier parasites are said to drink the blood of their host.
Fish suffering from the parasite tend to be underweight, probably because having something living in their mouth and pretending to be their tongue so it can eat messes up their diet.
The tongue-eating louse does not kill the fish it hooks itself onto, but when the fish eventually dies the parasite leaves the mouth.
What happens to the parasite afterwards is unknown and possibly best left that way.
According to Wikipedia the parasite starts life as a juvenile creature which become males once they've attached themselves to the gills of a fish. Once they mature they become females, which then make their way into the fish's mouth and replace the tongue.
Fortunately, the parasite is not very harmful to humans, the worst it can do is bite a person that tries to handle it, at only a few milimetres long it's much too small to cut off a human's tongue and attempt to replace it.
They are mostly found in waters around North and South America, though there have been a few people who have found them in the UK.
Luckily those are isolated incidents from fish which have come from areas the parasite is normally found and don't seem to be indicative of a wider trend.
The tongue-eating louse featured in the 2012 horror film The Bay, naturally they were the bad guys in that movie.
Featured Image Credit: Galveston Island State Park - Texas Parks and Wildlife