This egg inside another egg is a perfect YouTube specimen

Which came first: the chicken, the egg or the second egg?

Okay, we don't know, but we do know this: amid all the late-night clips and VEVO spam, there occasionally emerges a popular YouTube video that is just weird and cool.

Behold: the stunning 2017 film "Egg Inside an Egg."

The clip goes pretty much how you'd expect. A mysteriously large egg is opened to find -- surprise! -- another, smaller egg inside. When they crack open the second egg, there's just a yolk, although it is slightly paler than most yolks.

This egg-inside-egg phenomenon is called a counter-peristalsis contraction. Basically, it's when an egg that has already passed through the hen's oviduct gets sucked back up before it can finish developing, allowing another egg to develop around it.

Poultry Science editor Gregoy Bedecarats detailed the whole phenomenon to BuzzFeed in 2013: "Sometimes, if you have another ovulation before the first egg is laid, you have a ‘counter-peristalsis contraction,’ which means the oviduct will contract upward, and the first egg will be moved back up."

"When you see a tiny egg incorporated [in a larger one], it means the egg was still present in the shell gland, and got sucked back up the oviduct to where the other egg was having its white deposited," he said.

Then, voilà -- a mega-egg.

And, as you may have noticed, the mega-egg is very big -- so big, in fact, that the guy who made the video was surprised it "didn't kill [his] hen" on its way out.

He also wrote that everyone in the room was too scared to eat the egg, so his wife used it to make hair conditioner.

Here's how to do that, in case you're curious:

See? The internet just keeps on giving.