Eris

Eris is named after the Goddess of Strife or Discord (a very musical name). It is a very distant planet compared to most of the planets we know, and it goes furthest of above the plane of the ecliptic of the 11 planetoids considered here.

Said to be composed of methane, water and rock for the most part, Eris has very slow seasons because of its very distant path around the Sun.

“Eris is the most massive and second-largest known dwarf planet in the Solar System. It is a trans-Neptunian object (TNO) in the scattered disk and has a high-eccentricity orbit. “(wiki)

“Eris displays very little variation in brightness as it rotates due to its uniform surface, making measurement of its rotation period difficult. Precise long-term monitoring of Eris's brightness indicates that it is tidally locked to its moon Dysnomia, with a rotation period synchronous with the moon's orbital period of 15.78 Earth days. Dysnomia is also tidally locked to Eris, which makes the Eris–Dysnomia system the second known case of double-synchronous rotation, after Pluto and Charon.” (wiki)

“Models of internal heating via radioactive decay suggest that Eris could have an internal ocean of liquid water at the mantle–core boundary.”(wiki)