They come back every 17 years.  And this is the year the Cicadas are set to come back in force.  The  'Cicada-Apocalypse' will commence once the temps warm up a bit.

Colossal numbers of cicadas have been maturing underground since 1996 and are ready to descend on the U.S. East Coast roughly along a 900-mile stretch from northern Georgia to upstate New York.  They're talking billions of the bugs doing their buggy thing all summer long.