What's the most expensive egg you can buy?

Can you tell me, what is the most exorbitant egg on the market that one can purchase? Is there a particular type of egg, perhaps from a rare breed of chicken, that commands an astonishingly high price? Are there any unique factors that contribute to its high cost, such as its nutritional value, rarity, or perhaps a story behind it? I'm intrigued to learn about this luxurious egg and its characteristics that make it so sought-after.