An origami-inspired robot arm made with material from cotton plants and pigs biodegrades when no longer needed. Such a soft robot could be further developed to carry out medical procedures inside the body and then pass safely through it. Soft robotics is a growing field because there are a number of applications where a hard, rigid device would be unsafe or unwelcome, such as when working in extremely tight spaces in machinery or in close proximity to – or even inside – people. Most experimental soft robots are made with synthetic materials such as silicon rubber. Now, Hanqing Jiang at Westlake University in Zhejiang, China, and his colleagues have created a simple version from cellulose derived from cotton and gelatin from pigs, which then biodegrades harmlessly.