Leeches

Real worms don't eat bacteria. Leeches are segmented, eucoelomate worms of the phylum Annelida, distinguished from other annelids by anterior and posterior suckers used for locomotion and feeding — on blood or soft body parts of other animals. They are not to be confused with nematodes, which lack these (and most other) features. Leeches are mainly aquatic, but the Asian land leeches are well known to trekkers. Annelid systematics is messy, but leeches are clearly united with earthworms and their ilk into a monophyletic grouping of hermaphroditic annelids, Clitellata, named for the specialized midbody segments (clitellum) that secrete a cocoon to surround the eggs.