crazy parasite

Once C. exigua replaces the tongue, some feed on the host's blood and many others feed on fish mucus. They do not eat scraps of the fish's food. This is the only known case of a parasite functionally replacing a host organ.

http://en.wikipedia.org/wiki/Cymothoa_exigua

Anyone who uses the phrase "easy as taking candy from a baby" has never
tried taking candy from a baby.
-- Robin Hood