Space.com calls it the weirdest object in the solar system, not me (I'd say Enceladus gets that title).
It's called Haumea, a dwarf planet named after the Hawaiian Goddess of fertility and childbirth. Originally it was named "Santa," as it was discovered around Christmas back in 2004, but the folks in charge of those things made them change it. It's from the Kuiper belt, a bunch of rocks between Neptune and the Oort Cloud. Just like Pluto.
It rotates so fast - a day is 4 hours - that is no longer round, but rather football shaped. It has a couple moons. And just recently they found a big red spot on it. No one knows what the spot is, though the theory is it minerals beneath the ice that were uncovered by a recent impact.
Sounds like a good candidate for an artificially made object to me. I'm not saying it is. I'm saying it's fun to think about. That red spot is a landing strip. Or a giant red eye.
H.P Lovecraft's Cthulus Mythos said there was a race of ancients called the My-Go who lived on a planet called Yuggoth. He patterned it after Pluto, but maybe he was off a couple dwarf planets:
"Yuggoth... is a strange dark orb at the very rim of our solar system... There are mighty cities on Yuggoth—great tiers of terraced towers built of black stone... The sun shines there no brighter than a star, but the beings need no light. They have other subtler senses, and put no windows in their great houses and temples... The black rivers of pitch that flow under those mysterious cyclopean bridges—things built by some elder race extinct and forgotten before the beings came to Yuggoth from the ultimate voids—ought to be enough to make any man a Dante or Poe if he can keep sane long enough to tell what he has seen..."
—H. P. Lovecraft, "The Whisperer in Darkness"
There is, according to the mythos, a hideous creature - Cxaxukluth, and I won't even try to pronounce it - kept in a pit on Yuggoth. So maybe the red spot is the Cxaxukluth pit.
I'm just sayin'.