The Cymothoa exigua (not easy to come out with at a party) gets inside the mouth of the Red Snapper through the gills. It sticks to the tongue and drains the blood out of it as it grows, causing the tongue to slowly atrophy. The parasite finally replaces completely (physically and functionally) the missing organ. The fish is then capable of using its “new tongue” normally. From this point on, the parasite does not cause any more harm to the host, and feeds only on the mucus the fish exudes.