The quagga mussel, identified as one of the world’s most harmful invasive species, is spreading throughout the United States’ Great Lakes. Originating from beyond the border, these mussels are disrupting the native ecosystem and outcompeting local species for resources. Their proliferation poses a significant threat to the health of the lakes, impacting both wildlife and water quality. This invasion highlights the challenges of managing transboundary environmental issues. The mussels reproduce rapidly and have few natural predators in the Great Lakes, making control difficult. Experts are currently studying the long-term effects of this species and exploring potential mitigation strategies.