For example, Jupiter has auroras, but they don't behave in the same way as Earth's auroras.
Jupiter has the most powerful auroras in the solar system, so the team was not surprised that electric potentials play a role in their generation. What’s puzzling the researchers, Mauk said, is that despite the magnitudes of these potentials at Jupiter, they are observed only sometimes and are not the source of the most intense auroras, as they are at Earth.
Saturn has a big hexagon on its north pole.
There's the infamous Tabby's Star.
Astronomers have hypothesized that the objects eclipsing KIC 8462852 could be parts of a megastructure made by an alien civilization, such as a Dyson swarm, a hypothetical structure that an advanced civilization might build around a star to intercept some of its light for their energy needs. According to Steinn Sigurðsson, the megastructure hypothesis is implausible and disfavored by Occam's razor and fails to sufficiently explain the dimming. However, he says that it remains a valid subject for scientific investigation because it is a falsifiable hypothesis. Due to extensive media coverage on this matter, KIC 8462852 has been compared by Kepler's Steve Howell to KIC 4150611, another star with an odd light curve that was shown, after years of research, to be a part of a five-star system. The likelihood of extraterrestrial intelligence being the cause of the dimming is very low; however, the star remains an outstanding SETI target because natural explanations have yet to fully explain the dimming phenomenon.
And, most relevant to me, is the mysterious Hoag's Object:
I say "most relevant" because Hoag's Object was the inspiration for the Wheel of Fire galaxy. I saw the photo, and then I started to wonder about it, and, well, the rest is history. Or the future, I guess, since most of the series has yet to be written.