The mating process between anglerfish is not beautiful or romantic. Instead the mating process is something that is closer to a scene in a horror movie. When the anglerfish mates the males physically fuse with female. Some species only fuse for a limited time while others are for life. When the fish are fused they share blood, sperm, and skin. This makes the anglerfish the only known animals to mate in a parasitic way. The question that comes from observing these fish is how do they mate without compromising their individual immune systems. Thomas Boehm, an immunologist at Max Planck Institute of Immunobiology and Epigenetics in Freiburg, Germany studied 31 preserved anglerfish representing 10 different deep-sea species. Of those that do fuse to mate they found they are missing genes that help produce new antibodies. These antibodies are supposed to be there to get better at binding to perceive threats in the future encounters, however anglerfish lack any sign of them. Further study found that two species that fuse to mate don't make any antibodies at all. This is intriguing because this leads to the idea that a species are fighting pathogens without antibodies. More study is needed to find out how such a method is possible but it opens a new world of study in finding ways to fight disease.