For the first time, a soft robot has been built that moves on its own with no batteries or cables.

It comes from the School of Engineering and Applied Sciences (SEAS) at Harvard University - and it takes the form of a 7cm pneumatic octopus.

The "octopod" can't walk or swim, but it raises alternating sets of legs in a very slow, eight-legged can-can.

Researchers say it is a key step on the path to making soft robots that can help in messy. real-world situations - like surgery - where rigid robots fail.

Footage: Lori Sanders, Ryan Truby, Michael Wehner, Robert Wood and Jennifer Lewis - Harvard SEAS.