'They Are Back!' People Across US East Coast, Midwest React to Invasion of 17-Year Cicadas - Videos

Billions of so-called Brood X cicadas have made their return to the East Coast and the Midwest after 17 years of hibernation.

John Cooley, an entomologist at the University of Connecticut, explained in an interview with NBC why the emerging of the cicadas is so special:

"It's such a unique experience because they really take over for a month or so...There may be trillions of ants around, but most of the time you don't pay any attention to them. These are big, loud, funny-looking, charismatic and active insects, and you really can't ignore them," Cooley said. 

People have been taking to social media to share videos of the cicadas as well as their reactions to the insect invasion.