Every so often, a video of some robot or other will make its way around the Internet. You're going to get one now. But this robot is different from those other robots for one very notable reason: none of those robots were inspired by invertebrates.
This little bundle of creepiness comes from Harvard, out of the lab of one George Whiteside. The basic idea is that the robot is powered by compressed air (note the trail of wires). The outer layer is made of something they call "elastomers", which I suppose is as good a word as any, and inside are some compartments, acting as balloons. Inflating, deflating and compressing certain compartments at certain times makes the robot move and walk.
And yes, before you ask, it can walk on Jell-O.
As IEEE Spectrum notes, "You could probably smash this thing with a hammer a whole bunch of times and it would still keep coming for you. And that's part of the idea." So, have fun with that line.
'Soft' robots like this are becoming more and more common; this is just the first one you're likely to have seen. Researchers are working on how to give robots more fluid movements that a more rigid traditional-looking robot can't do. There are two main problems to work out: the potential for puncturing, and the external power source (again, note the wires).
Of course, those external power sources may be the only thing giving humanity hope to stop them. After all, hammers won't work.