Seanna

Seanna is the third and largest moon of the planet Manta in the Odjoran system. The entire moons surface is covered with water making it an endless ocean.

It's a cold ocean moon.

Surface
Seanna's surface is entirely covered with water, there are no landmasses. The ocean of Seanna is over 20 km deep at average with the deepest point being 42 km below sea level. At these depths the water pressure is so crushing that the Water is forced into solid form, effectively creating Ice-7 on the ocean floor. On other places on the other hand it can be as shallow as 200 meters deep.

Ring system
Seanna also has a ring system. These rings probably are all that remains from an asteroid or comet which passed to close to the moon. There are two distinct rings which together extent from 7260 to 20000 km from the planets center of mass. The gab is caused by tidal distortions as the moon does not have any orbital satellites.

The ring system has a life expectancy of roughly 100,000 years before it will be torn apart by gravitational forces in the Manta system.