Scientists have created robots that can change shape between solid and liquid states, which allows them to perform incredible tricks – jumping, climbing and even escaping from a cage, reminiscent of the T-1000 robots from the Terminator franchise.

The shape and movements of machines are controlled by magnetic fields, an approach that could lead to new biomedical and engineering technologies, such as targeted drug delivery, circuit assembly, or the creation of universal screws.

Soft robots are much more flexible than their rigid counterparts, but the trade-off is that they are not as strong, fast, and easy to control as rigid machines.

An international team of engineers has developed a material made of gallium metal, in which magnetic microparticles are embedded.

This “magnetoactive phase transitional matter” (MPTM) uniquely combines the high mechanical strength, load capacity and displacement speed of the solid phase with “excellent morphological adaptability (stretching, splitting, and merging) in the liquid phase,” according to the study, published in the Matter journal.

“People have been working on these small, magnetically responsive robots and machines for a long time,” said Carmel Majidi, director of the Soft Machines Lab at Carnegie Mellon University and senior author of the new study, in a call with Motherboard. “In parallel, my group has developed many techniques that use liquid metals — metals like gallium that have a very low melting point.”

The machines the team created are able to respond to magnetic fields thanks to magnetic microparticles in their “bodies.” By placing the robots in an alternating magnetic field, Majidi and his colleagues from Sun Yat-sen University and Zhejiang University in China make them move and even heat them up, causing them to liquify.

“If you have a metal that’s subjected to an alternating magnetic field, we know from the basic principles of electromagnetism that this essentially causes electric current to spontaneously flow through that metal,” Majidi explained. “It is this spontaneous electric current that heats and melts the metal.”

Using this technique, the researchers were able to get MPTM robots to solder circuits, shape themselves into a universal screw, remove objects from a dummy’s stomach and overcome obstacle courses.

They were also able to make a cute little LEGO man out of MPTM that liquefies and moves through the bars of the cage.

The ability of robots to dynamically transform can be adapted to perform many functions, especially in biomedicine.

Future iterations of the MPTM machines will be able to deliver drugs to specific organs or extract dangerous objects from the body. The ability to switch between solid and liquid states can also be useful for accessing any confined or hard-to-reach spaces.