Sometimes I'm surprised by something I thought I knew, and found out I didn't, not really. For your consideration: NGC 1427A, a dwarf galaxy.
[Click to unendwarfenate.] I've seen pictures of this little guy before. It's a small galaxy, maybe 20,000 light years across (the Milky Way is 5 times that size), and part of the Fornax cluster, a small but rich cluster of galaxies about 60 million light years away. The picture here was taken with the monster 8.2 meter Very Large Telescope in Chile, and uses filters that give a somewhat true-color appearance, though it also accentuates warm hydrogen (the pinkish glow). Even though I've looked at it before, I don't think I really saw it, because the boomerang shape is obvious, and to anyone familiar with galaxy dynamics the reason behind it is obvious too. Maybe it'll help to know that this diminutive galaxy is screaming through ...
