There’s a reason some people feel lucky when discovering two yolks inside a single egg. Double yolks are rare—they occur in roughly one of every 1000 eggs. As Sploid reports, a family recently discovered something even more remarkable laid by their hen. They cracked open an egg to find not just a bonus yolk, but an entire bonus egg kept perfectly intact.
The phenomenon, while uncommon, isn’t unheard of. It’s called counter-peristalsis contraction, and it happens when a second egg starts forming before the egg that precedes it exits the hen’s reproductive system. In such cases, the new oocyte (the part of the egg that becomes the yolk) moves through the chicken’s oviduct per usual, collecting membranes and albumen (the white part) along the way. If a fully formed egg has been contracted back into the oviduct from the uterus, the whites of the still-forming egg will amass around it.
The result is a Russian-nesting-doll situation at the breakfast table. According to the uploader of the video above, no one was brave enough to eat the egg or the egg-within-the-egg, but it didn’t go to waste: It was used to make hair conditioner the old-fashioned way instead.