As if the line between human and machine wasn't already blurry enough, researchers in Tokyo have developed a new method for using living rat muscle tissue in robotics.

The “biohybrid” design, described today in the journal Science Robotics, simulates the look and movements of a human finger. Video shows how it bends at the joint, picks up a loop, and places it down. It's a seemingly simple movement but one that researchers say lays the groundwork for more advanced—and even more lifelike—robots. (Meet Sophia, the robot that looks almost human.)

“If we can combine more of these muscles into a single device, we should be able to reproduce the complex muscular interplay that allows hands, arms, and other