Spores of the parasite H. salminicola swim under a microscope. Those alien "eyes" are actually stinger cells, one of the few features this organism hasn't evolved away. (Image credit: Stephen Douglas Atkinson) When the parasitic blob known as Henneguya salminicola sinks its spores into the flesh of a tasty fish, it does not hold its breath. That's because H. salminicola is the only known animal on Earth that does not breathe.If you spent your entire life infecting the dense muscle tissues of fis...