Over the weekend, thousands of poisonous baby cane toads emerged from canals or leapt out of retention ponds in several Palm Beach Gardens neighborhoods along the Atlantic coast of Florida.

The giant knot—which is the name for a collective group of cane toads—likely settled in after mild winter temperatures and recent rains set the toads up for a booming breeding cycle, with thousands of baby toads reaching maturity around the same time, reports Chad Gillis at USA Today.

The species, Rhinella marina, used to be known at Bufo marinus, and many people still refer to the cane toads as bufo toads. A native of Central and South America, the species first made it to Florida in the 1930s in an effort to control sugar cane pests. In 1955, a pet dealer accidentally released about 100 toads at an airport, reports Eli Rosenberg at The Washington Post. Additional releases in the 1960s also helped establish wild populations of the toad in parts of the state.

Cane toads can be dangerous to pets and wildlife. According to the University of Florida Wildlife Extension, the species releases a toxic substance from a parotoid gland behind its ears. The toxin is strong enough to kill cats or dogs that munch on the toads and can cause burning eyes or skin irritation in humans that handle the critters.

The biggest concern, however, is the environmental damage they can cause. The species breeds year round and has a pretty unrestricted diet for an amphibian: it eats everything. They nosh on pet food, food scraps, carrion and just about every type of insect there is, reducing food available for other species. They also prey on smaller native species of frogs, toads, snakes and mammals. When local predators try to eat them, they are often poisoned by the toads. In many ways, the cane toad is a one-species ecological wrecking ball.

Australia has been particularly bull-dozed by the toads. In 1935, 101 of the amphibians were released in the tropical north of the country to help control beetles attacking sugar cane. In less than 100 years, the species has multiplied to over 2 billion toads and the horde is marching westward, threatening the continent’s endangered lizards and mammals.

In Palm Beach Gardens, the current problem isn’t impact on natural habitat, it’s simply the sheer quantity of toads that have emerged. In some areas, people can’t walk outside or drive for fear of squashing the amphibians. There are so many they are even clogging pool filters.

“I just see a massive amount of toads or frogs everywhere, covering every square inch,” Jenni Quasha, who lives in the Mirabella neighborhood, tells NBC affiliate WPTV. “You can’t even walk through the grass without stepping on one. I’m worried about people’s pets, so there’s definitely no swimming in the pool or playing outside and enjoying the outdoors.”

Mark Holladay, a lead technician with local extermination service Toad Busters, tells WPTV that the swarm-like conditions aren’t likely to go away soon. “There will be another influx like this in 22 days when the next batch hatches out, and this is in every community in Florida.”

The toads have also become established in Hawaii, Guam and Puerto Rico, where they were also introduced to control sugar cane pests. A small population of cane toads is found in the Rio Grande Valley in far southern Texas, which is the most northern point of their native range.