In my early days as a reporter, I learned to chase photographers the way that dogs chase cars, instinctively. That’s how, at last week’s Flood Wall Street protest, I wound up underneath the carbon bubbles. They were big, black, and silver and looked like enormous beach balls, and they were being held aloft by a horde of people surging down Broadway in the direction of the protest’s intended target: Wall Street.

I had seen them being inflated earlier, at the staging area in Battery Park, and hadn’t thought much of them. But now, seeing them surrounded by the skyscrapers of the financial district, they looked striking, both as art and as visual shorthand for a pretty abstract and wonkish economic concept — the risk represented to the world’s economy by allowing energy companies to base their value on coal and gas reserves that we can’t actually use without making climate change intolerably miserable.

DIY inflatables have been around since the ’70s, but I hadn’t ever seen them deployed at a protest before. They looked more like pop art than the social realism and folk stylings that I’d seen both elsewhere at Flood Wall Street and at the People’s Climate March the day before. “What is your story, bubbles?“ I wondered, as they were batted back and forth, squeezed in between tour buses, and eventually confiscated by the police and stomped on. “Where do you come from?”