This is kind of a robot snake in reverse: it's designed to float just beneath the surface of the sea and capture wave energy, which it then turns into electrical power. A science team in the UK has been working on the design, and is now testing small versions in a test tank: ultimately the "real" machines would be 23 feet across and 650 feet long, and be able to generate 1 megawatt. Check out the video to see how "Anaconda" works.
Basically the rubber snakes are moored at the right height to bend as a wave rolls past, generating a bulge in the sea water inside. This gets pushed down the tube by the wave to a generator built into the tail end.
A full-scale device would be able to generate enough power for 1,000 homes, and the developers at the University of Southampton think it may be more resilient than other wave-generators due to its lower moving part count, and the fact that it's made mostly of materials that resist salt-water corrosion.
Plus, it looks satisfyingly sci-fi, in a scary surprise for divers kinda way.