“There’s a lot wrong with this picture,” joked WHOI scientist Rob Reves-Sohn. “A cat … in the water … on a leash.” But then it came time to unleash the cat—a robotic vehicle nicknamed “Puma”—for a test dive below the Arctic Ocean surface. “We’ve been developing these underwater robots to attempt to go where no robot has ever gone before,” Reves-Sohn said. “… And come back,” WHOI engineer Hanu Singh added quickly. Puma (short for “Plume Mapper”) is designed to swim freely in the depths to search for plumes from hydrothermal vents on the seafloor. Before its test today, the vehicle’s torpedo-shaped outer “skin” had been newly adorned with a sleek silver-painted puma and the flags of the United States, Sweden, Germany and Japan.