Fast-spreading parasite species force sex changes on their victims, induce virgin births, Water found on a potentially life-friendly alien planet.
An alien parasite transforms males to look like females, and hijacks their the microscopic barnacles enter the crabs and change their sexual.
I would like to introduce you all to Cymothoa exigua, or the tongue eating louse. Cymothoa exigua is an isopod (like crabs or lobster) and is a fish parasite. It is the only known organism to replace an entire organ of its host species, in this case, the poor fish’s tongue.