Now multiply that by a billion, and that's how many of the squirming insects are estimated to be nesting in trees throughout parts of the state, especially Whidbey Island.
"There's too many of them, way too many of them. They're awful," said resident Patrice Huth, who just watched a caterpillar drop from a tree branch onto her shirt.
The tent caterpillars build cocoon-like nests in alder trees that look like elongated sacks, sometimes containing hundreds or thousands of them.
They devour the leaves, and often move onto to other trees like pear, apple and cherry. They also attack rose bushes.
"They are so destructive, and they're everywhere," said Huth. "They can ruin backyards, and they can decimate fruit orchards. This is just a really bad year."
Experts with the WSU Extension Service say we're experiencing an especially large caterpillar bloom, attributed to a variety of environmental variables, , including weather and parasite populations.
The caterpillars emerge every year, but their numbers explode once or twice a decade. Some locals say it seems like about every nine years.
"This time around it's bad. They've stripped one of our beautiful cherry trees bare," said Maureen Murphy, owner of Bayview Farm and Garden. "We've been conducting patrols around the nursery, trying to fend them off the best we can."
Murphy says the millions of caterpillars that devoured her Cherry tree have already crawled away. She watched what she described as millions of them making their way from the tree, searching for a place to build cocoons.
"The worst is almost over. Soon you'll see their cocoons everywhere. In a few weeks they'll hatch into moths," she explained. "By middle or late summer they'll lay eggs, setting up the cycle for another explosion next year. And I think it's going to be worse then."
There are commercial sprays that can help fend off the insects and a home remedy using dishwashing soap. Most trees will survive, though they look ugly after the feasting.
"I don't want them eating my nursery," she said.
Throughout parts of Whidbey Island, the caterpillars are crawling over just about everything, including mailboxes, railings, parking lots, and sometimes people.
"Customers will walk in and we'll see one or two on their shirt. We just kind of laugh and let them know. It's no big deal, but some people don't like them at all," said Murphy.
The insects do have a couple benefits for the environment. They will provide a feast for birds and bats and other animals. And their droppings serve as a fertilizer for trees, particularly new conifers.
"You can hear their poo," explained Murphy. "It will fall all around you, you think it's raining and you look around and nothing's wet and you don't know what's going on. But it sounds like it's raining."
While we were shooting video of hundreds of nests in a grove of Alder trees, we heard what sounded like a faint crackling everywhere. Though we couldn't see it, we now know we were standing beneath a cascade of tiny caterpillar droppings.