Cymothoa exigua: Biting Your Tongue, So You Don't Have To. When fish mommies want to strike fear in the hearts of their misbehaving fish babies, we suspect they draw on the chilling animal savagery of the Cymothoa exigua. As a youngster, this nasty little parasitic crustacean begins a life of terror by fighting its way through the gills of its fish host of choice, the snapper. Once there, it attaches itself to the fish's tongue and begins feeding on the rich blood pumping through the artery underneath. As the parasite grows, it drinks more blood and eventually causes the tongue to atrophy and disintegrate. But does the Cymothoa mouth-squatter leave its fishy friend tongueless? Of course not. It does any craft parasite would do and replaces the old tongue with its own body. The fish is actually able to use the parasite just like a normal tongue, only it has to share all the food with its new friend. Yes, the whole foster-tongue thing seems like a pretty nice gesture on the part of ol' Cymothoa - until you remember there was nothing wrong with the fish's old tongue in the first place. Previously on Neatorama: When Exigua Got Your Tongue, It's For Real