Scientists in the US have created an artificial jellyfish that can swim just like the real thing.
They created the replica by putting heart muscle cells from a rat into a silicone base.
Then they shocked the fake jellyfish with electricity and made it swim.
The team at Caltech and Harvard University want to carry out further work on the artificial jellyfish to make it change direction.
They also plan to incorporate a simple "brain" so the jellyfish can respond to its environment and even detect and move towards a light source.
They hope the creation could be used to test medicines for heart problems and even help with designs for artificial hearts in the future.