A Harvard scientist has created a light-driven robotic stingray powered by the heart cells of genetically modified mice. And if that isn’t the most sci-fi sentence you’ve read in years, you’re either doing something terribly right or horribly wrong.

Bioengineering, the field of science responsible for this strange and almost abstract breakthrough, is a relatively new discipline. It focuses on the application of engineering methods to biological or medical components in order to solve real-world problems. Bioengineers work on everything from creating new medical equipment, to programming the DNA inside a living cell, to creating entirely new out of living tissue.

One of the biggest goals of modern bioengineering, for years now, has been the creation of human organs from scratch. Such a breakthrough would completely change the medical world- imagine if patients would no longer have to wait years for a viable donor, and could instead just custom order a healthy copy of their own organs, possibly even created from their own cells. In theory, these artificial organs would be created by a 3D printer, using cells instead of ink, slowly laying down layer after layer of the organ on top of one another until the entire organ is finished.

However, this technique is far from being perfected. 3D-Printed tissue tends to be much more fragile than the real deal, and so far it’s been almost impossible for it to survive long enough to even be grafted into a living body. It was only recently that any sort of breakthrough was achieved, when scientists were able to attach an artificially created ear to the head of a mouse.

And then there’s the problem of complexity- human organs are large and tend to be very complicated, and there are some doubts that we would even be capable of artificially creating something similar. Those doubts were exactly what Kevin Parker wanted to address when he set out creating an artificial robotic sting-ray powered by genetically altered mouse heart cells.

The tiny bio-bot is more complicated and refined than anything that had previously been created using living tissue in this way. The heart cells have been reprogrammed to beat in response to certain wavelengths of light, before being carefully printed in a specific pattern on the “wings” of a penny-sized plastic stingray.

When the light is shone in the water near the robot, the stingray will swim towards the light as the heart cells contract in a specifically programmed pattern, causing the wings to flap in just the same way that a real stingray’s do.

In theory, this is the exact same process as creating a human heart from scratch. Programming the cells to react in a certain way to specific stimuli, and then arranging them in a very specific pattern in order to produce a very specific effect- it’s the same thing that bioengineers might be doing in the very near future to print functioning humans organs. It’s a sort of prototype, a test run to prove that it’s possible.

So even though a tiny plastic fish, driven towards light and powered by the cells of genetically re-engineered mice, might seem a little bit nuts, it’s actually a big step towards solving one of the most ambitious medical problems of the twenty-first century.