The Still World is a dimension in Echoes of Wisdom. It serves as a parallel dimension, having the same contents as areas in Hyrule that have been consumed by Rifts. When people fall into rifts, they are transported to the Still World in a paralysis-like condition, unable to talk or move.
The only beings known to be able to move normally in the Still World are Null, Null's monsters, Tri, Princess Zelda, and Link.
Additionally, the objects in the Still World float around, frozen in the state they were in when they were consumed by a rift. Gravity doesn't affect paralyzed/frozen objects in the Still World, but gravity is normal for beings capable of moving inside this realm.
Eventually, everything in the Still World will disappear if the Rift is not mended in time.