These were hired goats.

The truck, according to KTVB.com, belongs to We Rent Goats, an Idaho-based company that does exactly what its name suggests. Goats, it turns out, are like cute, furry lawn mowers. They love to eat common weeds (and the seeds that lead to more) that many homeowners don’t want on their lawns. “Thorns and plants that cows and sheep don’t like are a delicacy for goats,” the We Rent Goats website explains. Grasses remain mostly untouched. The result? A weed-free, verdant lawn.

We Rent Goats and other goat-renting companies—and there are others, many, many others—say this method of landscaping provides an environmentally friendly alternative to pesticides and bulldozers. The company usually leaves the animals to feast with minimal supervision. “If your property is in a high traffic area or in the middle of town, we will have an employee on duty full time,” their website explains. “If the property is in a remote area, we’ll check the goats at least two times a day.” But the goats don’t come with a sign or other indication that explains to curious passersby, including Parris, why they’re there.

We Rent Goats responded to a request for comment Friday night, after the photos and videos had been widely circulated online.

“I definitely did not think that goats, certainly not my goats, would ever be the talk of the internet,” said Matt Gabica, who runs the company with his wife, Kim. “I don’t really do the whole social media thing, plus I was pretty busy today making sure all the goats were safe and sound and fielding phone calls from all over the country, so I don’t honestly know what all is happening on the internet. But I’m getting a lot of messages from people saying our goats went viral. Whatever that means.”

Gabica said the goats—118 of them—went rogue from their assignment on Friday. The goats were dispatched to a storm-water retention pond, about two blocks from where the local news reporter found them, to munch on noxious weeds. But they apparently escaped through a couple wood boards that worked loose as they leaned against the boards to stand up on their back feet and eat the tops of some tall weeds,” Gabica said. “Once they escaped they began wondering through the neighborhood that the pond is in the middle of, and they were found by the community of folks that live in that neighborhood.”

When Gabica learned of their escape, the company rounded up the goats and took them to their next job, “where the fence is much stronger,” he said.

The idea of using livestock as landscapers has been around for decades. In 1918, Woodrow Wilson brought in a flock of sheep to trim the White House lawn.

When it comes to rental goats, the more the better. “You can’t just have one goat,” Kari Dodd, an employee at the Tehama County Farm Bureau in California, told Modern Farmer in 2013, for a story about the phenomenon. Goats are social animals and prefer to roam in groups. The We Rent Goats website says the company prefers to use at least 100 goats per job, who can collectively consume about a half acre of vegetation per day.