Vanessa Alarcon saw them while working at an antiwar rally in Lafayette Square last month.

"I heard someone say, 'Oh my god, look at those,' " the college senior from New York recalled. "I look up and I'm like, 'What the hell is that?' They looked kind of like dragonflies or little helicopters. But I mean, those are not insects."

Out in the crowd, Bernard Crane saw them, too.

"I'd never seen anything like it in my life," the Washington lawyer said. "They were large for dragonflies. I thought, 'Is that mechanical, or is that alive?' "