Scientists have created a tiny, ingestible robot made from pig intestine that might be able to retrieve swallowed objects without surgery.

The robot is built from a magnet attached to folds of dried meat typically used in sausage casings. It needs no tether or power source, instead being guided by magnets outside the body. Though swallowed in an ice capsule, the robot unfolds inside the stomach as its casing melts.

Scientists from MIT, along with collaborators in the UK and Japan, recently tested their meat robot's ability to retrieve a button battery, like the kind used in watches. The team bought a pig stomach and used it as a guide to design a silicon cross-section of the stomach. They filled the model stomach with water and lemon juice to stand in for stomach acid, then dropped in the button battery.