Remoras are nature’s suction cups. The ray-finned fish can hold on tight to anything: boat hulls, jumping dolphins, even human divers. Also called suckerfish, their strong grip comes from an adhesive disk made from a modified dorsal fin on the fish’s head. Now, researchers report that they have engineered a robot to do the same thing. Like the fish’s specialized sucker, the “biomimetic remora disc” can make a tight seal using the same circular pattern as the fish. And its rows of flaps, dotted with tiny spikes, allow it to raise and lower how close it is to the surface. To test how well this sucker worked, researchers attached it to a remote-controlled submarine. When the researchers directed the robot to attach to a submerged material, like plexiglass or sharkskin, the sucker grabbed onto both in less than 4 seconds on average, holding fast until researchers pulled it off. Once stuck, it took 45 kilograms of force to remove it, they report today in Science Robotics. That’s about 340 times the disk’s own weight. The disk worked just as well on dry land as it did on water, without any noticeable loss of suction. The researchers say such systems could one day greatly extend the range of robotic undersea explorers.