Despite being one of the most alien-looking things on Earth, the mechanism jellyfish use to swim is similar in some ways to the beating human heart. That inspired researchers to build a sort of cyborg jellyfish from the ground up, using heart muscle cells from a rat and silicone polymer. And it’s actually only a little more odd-looking than a regular jelly.
The heart cells harvested from the rat were grown onto the silicone. When an electric current is sent through the water, the jellyfish—named “Medusoid”—contracts in a way that mimics a heart. The technique could eventually lead to scientists creating bio-engineered systems for humans, such as a pacemaker that works without batteries. The jellyfish could also make a good vessel for testing heart drugs before they’re used on humans.