Iapetus Ridge: https://en.wikipedia.org/wiki/Equatorial_ridge_on_Iapetus

Polar Storms of Jupiter: https://en.wikipedia.org/wiki/Atmosphere_of_Jupiter#Circumpo...

Hum, I just realized that those polar storms would turn easily into the hexagon if they just lose power (or would be covered by another layer of material over it). Both are probably the same phenomenon. More strong in Jupiter, less in Saturn. Tornados would explain also why is a tall shape

The hexagon should gyrate slower (with less energy) than the jupiter storms. Neptune should have also the same process but is colder I'm not wrong, so maybe it has less energy and is not so easily visible.

Yep, here is the Neptune hexagon... same pattern, same process

https://slate.com/technology/2014/05/neptune-voyager-images-...

More weirdness in our Solar System

Mimas - A moon of Saturn which from certain angles looks like a death star. [1]

Hyperion - Another moon of Saturn which looks like a sponge. [2]

Phobos - A moon of Mars with a huge crater on one end.[3]

[1] - https://en.wikipedia.org/wiki/Mimas_%28moon%29 [2] - https://en.wikipedia.org/wiki/Hyperion_(moon) [3] - https://en.wikipedia.org/wiki/Phobos_(moon)

And a bit more...

Phobos monolith

https://en.m.wikipedia.org/wiki/Phobos_monolith

Good ol Buzz, giving mention to the subject

https://m.youtube.com/watch?v=bDIXvpjnRws

Also, Mars monolith https://en.m.wikipedia.org/wiki/Mars_monolith

Europa is another intriguing spaceball, with the (vague if you must) possibility of a life-supporting ocean.

Edit: add mars monolith

Also, the co-orbital moons Of Saturn, Janus and Epimetheus.

https://en.m.wikipedia.org/wiki/Janus_(moon)

https://en.m.wikipedia.org/wiki/Co-orbital_moon