This parasite was almost one that was featured for Halloween - you'll see why soon - before worms in the eyes of giant birds and blood-lapping/swapping bats took over. But, this tapeworm is really fascinating, so I wanted to feature it now. Sanguilevator yearsleyi was recently discovered in the spiral intestine of a broadfin shark (Lamiopsis temmincki), in Sarawak, Borneo. Histological examination of the tapeworms' scoleces (plural of scolex) revealed spherical and transverse channels that were then found to contain white and red blood cells, respectively, suggesting that the tapeworm sorts and stores these host cells. Why it does this, though, is a bit of a mystery, as tapeworms lack a digestive system per se, and typically just absorb simple nutrients from their hosts.
Nominated by Joanna Cielocha and image comes from the paper describing the species.