When you look up in the sky, what do you see? Clouds, maybe. While it sounds a bit odd because of how we think of clouds as three dimensional figures, the clouds you see in the sky typically have “flat” bottoms. So if normal clouds have flat bottoms, what type of clouds have not-flat (aka round) bottoms? Mammatus clouds. What exactly do mammatus clouds look like? My, I’m glad you asked…

So mammatus clouds are… akin to chickenpox. Just kidding. (And, yes, that is a real photo — not photoshopped, you conspiracy theorists.)

[via NASA | image credit: Craig Lindsay]