The parasite whorl split off from its ancestor the whorl needler. It has gotten smaller and feeds off the blood of centifins and seadragolden. It will pry apart the exoskeleton and pierce its flesh with its 4 arms. Then injects a numbing agent so the host will not feel it as it drink up its blue blood.
When swimming it uses its small, extremely sensitive membranes are attached to the arms for navigation. The parasite whorl can make a high pitched sound allowing the membranes to pick up vibrations in the water, allowing them to navigate via echolocation instead of swimming randomly around.
They breathe by taking in water in a hole in the front of the creature then is expelled via smaller pores neat the tail. The large flagellum-like take wiggles in a corkscrew movement which causes it to swim in an ever turning corkscrew motion. The body is protected by hard spines, which can sting when touched.