Two rare dragon eggs, hatched in an aquarium at Postojna Cave, was a rare opportunity that science witnessed on Wednesday. An aquatic salamander known as the olm or proteus hatched eggs.

The first egg hatched on 30 May and was not witnessed by anybody, while the second was seen with a dragon squirming out from the egg. The offspring being completely blind and pale in color, these eggs are laid once or twice in 10 years. And they live up to 100 years, according to The BBC.

Saso Weldt takes care of olds at the cave. “I was in the cave doing some other biological work. Since we have all the eggs on an IR camera, we saw that one was missing,” He said. “Then you rewind and suddenly you realise, something has happened.”

Earlier this year, around 50 to 60 eggs were laid by a female, which took several weeks. Now, out of those, 22 embryos were developed. Other eggs were destroyed due to fungal infections in the water.

Now researchers’ curiosity level has taken a new flight of expectation. Of course, the rest are still to be witnessed hatching out of the shell within few weeks.

They are consulting amphibian experts to take extra care of the eggs.

“We are now keeping a close eye on the eggs to see which one will be our next baby dragon. Will it – like the first one – shoot out of the egg and swim around the aquarium, before finally coming to rest at the bottom?” said Postojna Cave in a report by Science Alert.

Two years ago, an olm laid eggs but was killed by other inhabitants of the cave.

Olds can grow up to 13.5 inches. They take 15 years to reach full growth. Initially, they seem like a pink worm and grow with four limbs. In spite of being blind, they have the ability to smell the food in their surrounding environment. Moreover, they can “live without food for a decade”.