A disturbing photo of a giant sea lamprey in a New Jersey river has gone viral.

Reddit user jlitch posted a photo of the massive, bloody creature caught in the Raritan River in Central New Jersey two weeks ago, and since then, photos of the catch have taken off.

The NY Daily News confirmed that the fisherman was Doug Cutler, who caught the lamprey with a bow and arrow. Cutler has turned down interviews, so it's still unclear whether the lamprey's size is accurate in the photo.

Lampreys are aquatic, jawless vertebrates that feed using a funnel-like mouth lined with teeth. Sea lampreys are parasites that feed on fish by latching on to their sides and scraping away the fish's tissue with its tongue. Lampreys can grow up to three feet in length.

The eel-like creatures are native to both coasts of the Atlantic Ocean, but are an invasive species in the Great Lakes region. There, lampreys prey on key species in the region, such as chub, lake herring, lake whitefish and lake trout. Lampreys have damaged lake ecosystems by diminishing the numbers of these apex predators necessary for ecosystem stability.

"The photo doesn't allow counting of gill openings (seven per side for sea lampreys), but based on size alone, this does appear to be a sea lamprey," a New York Department of Environmental Conservation spokeswoman told Outdoor magazine.

Sea lampreys, while not common in the area, have recently been spotted in New Jersey rivers. The Daily News suggests this may be because of aging dams being removed, giving the lampreys access from the ocean.