Cyro, a five-and-a-half-foot robot jellyfish autonomous robot is designed to "mimic the unique, efficient underwater propulsion of a jellyfish".
The autonomous jelly robot is the result of a grant from the Office of Naval Research. Alex Villanueva, a graduate student at Virginia Tech working on the Cyro, says, "It’s not necessarily the best hydrodynamics propulsion mechanism, but the jellyfish has a very efficient metabolism: energy going in comes out as hydrodynamic energy."
Did I mention that the giant freaking jellyfish robot is autonomous. That means there are no controls. It is a launch-and-forget fake jellyfish. What could possibly go wrong with that?
According to the article at Wired (with video), "There’s no saying whether the Navy will purchase the ‘bot, and its inventors are comfortable emphasizing its civilian potential as an oceanographic research testbed. But should the Navy decide it needs a surveillance tool that looks like a massive jellyfish, there’s one on offer."