The northern snakehead is a long, blotchy-patterned fish that can breathe on land and travel on the ground by wriggling its slippery body. But those might not be the species’ most nightmarish qualities. Snakeheads have a voracious appetit; they've been known to chow down not only on other fish, but also crustaceans, reptiles, mammals and small birds. They are invasive to the United States, threatening to displace native species and upset the balance of aquatic ecosystems. The fish have been reported in more than a dozen states across the nation and, as Christine Hauser reports for the New York Times, they have now been found for the first time in Georgia.

The slithering species was first spotted by an angler fishing in a pond in Gwinnett County. And Georgia officials have issued blunt instructions to anyone else who stumbles upon a northern snakehead: “Kill it immediately.”

After the fisherman alerted Georgia’s Wildlife Resources Division to the odd creature he had found, officials set out to the pond to investigate. They found an adult snakehead—possibly the one the fisherman had reeled in and then tossed back into the water—and three juveniles. Those snakeheads are now “[d]ead and frozen,” a fisheries operations manager with the Wildlife Resources Division, tells Hauser.

Snakeheads are native to Asia, Malaysia, Indonesia and Africa, where they exist in freshwater ecosystems with the appropriate balances to keep the fish in check. In decades past, snakeheads were sold in pet shops and live food markets in the United States, and are believed to have been released into natural waters by “aquarium hobbyists or those hoping to establish a local food resource,” according to the United States Geological Survey.

The first established snakehead population took hold in Maryland in the early aughts, and the animals can now be found “in every major tidal river of the Chesapeake Bay,” reports Lateshia Beachum of the Washington Post. In 2002, the fish were added to the list of injurious wildlife under the Lacey Act, which in turn banned the import and interstate transport of snakeheads.

“These fish are like something from a bad horror movie,” former Secretary of the Interior Gale Norton said when proposing the ban some 17 years ago. “They can eat virtually any small animal in their path. They can travel across land and live out of water for at least three days. They reproduce quickly. They have the potential to cause enormous damage to our valuable recreational and commercial fisheries.”

But in spite of legislative efforts to control them, four species of snakeheads have cropped up in 15 states, from New York to California—and even Hawaii. It’s not clear how the fish were introduced to Georgia, but the state’s Department of Natural Resources notes that “[i]nvasive species are often introduced through unauthorized release” and offers a friendly reminder that “it is unlawful to import, transport, sell, transfer, or possess any species of snakehead fish without a valid wild animal license” in Georgia.

Robinson tells Hauser of the Times that experts now plan to conduct genetic testing on the four snakeheads captured in the Georgia pond to see if the juveniles are related to the adult. At least one other parent, officials believe, may be still swimming free.