What caused this griddle-and-pancake-batter feature on the Moon?

Every now and again, I am strongly reminded that our Moon is really weird.

It has a ton of familiar features on it, so it's easy to get complacent. Giant impact craters, vast relatively smooth plains called maria (MAH-ree-uh) that are filled with dark magmatic basalt (which form the features we can see by eye on the Moon), and everything else a perfunctory examination through a small telescope reveals. Wondrous, yes; beautiful, absolutely; but the sort of stuff that we can mostly explain.

And then there's Ina.