leech

leech (http://definr.com/leech)

     n 1: carnivorous or bloodsucking aquatic or terrestrial worms
          typically having a sucker at each end [syn: bloodsucker,
           hirudinean]
     2: a follower who hangs around a host (without benefit to the
        host) in hope of gain or advantage [syn: parasite, sponge,
         sponger]
     v : draw blood; "In the old days, doctors routinely bled
         patients as part of the treatment" [syn: bleed, phlebotomize]