Trillions of cicadas will emerge across several U.S. states this spring in an event one expert dubbed "cicada-geddon." Not only are more cicadas than usual expected this year, but some of them will be "zombie cicadas" that are infected by a sexually transmitted fungus that makes them hyper-sexual. 

Periodical cicadas spend most of their lives underground and only emerge after 13 or 17 years. This year, two broods of cicadas will emerge: Brood XIX, which comes out every 13 years, will emerge in the Georgia and Southeast, and Brood XIII, which emerges every 17 years, will appear in Illinois. 

With this convergence, the bugs will arrive in numbers that have not been seen in generations. 

Matthew Kasson, an associate professor of Mycology and Forest Pathology at West Virginia University, says both of these broods can be infected by a fungal pathogen called Massospora cicadina.