You’re not likely to be find one at a pet store any time soon, but the world’s first glowing bunnies were born in early August in a Turkish laboratory. It’s no weird-science party-trick; researchers are testing a technique that will one day help make new medicines.

First, they extracted a protein from jellyfish DNA that makes it glow. Then they injected that protein into rabbit embryos in the lab. Once the embryos were implanted into a female rabbit, they grew into a litter of eight. Two of them glow green under a black light. They say it doesn’t hurt the rabbits at all, and under normal light, they don’t look any different from their siblings.

Of course, the researchers’ ultimate goal is not to make glowing bunnies. It’s to inject a different snippet of DNA into embryos that will make female rabbits produce a specific protein in their milk—a protein that can be used to make medicines to treat certain blood diseases.

So, why bother with the jellyfish protein? Because it’s a lot easier to know right away if the DNA transfer technique works when all you have to do is turn on a black light to see which bunnies have the gene.

Watch the video of the glowing bunnies.