S-Space

S-Space (Sub-Space) is the physical embodiment of thoughts of those in R-Space, similarly to how R-Space is made up of Q-Space's thoughts. It is likely that Zoom, Varunia, Anti-Space and the Shadow Realm are parts of S-Space. Also, Fanventures, aside from Super Mario Brothers Fanventure 2, takes place in S-Space.

One could assume that characters such as Flutter and Yami Yoshi are, if not from S-Space themselves, then at least descended from S-Spacers. At one point I'm pretty sure Flutter and Big Al were treated as being from S-Space (although that was when Flutter was actually Sgt. Flutter). As for Yami, I had some vague theories explaining that as to how Yoshi's Island wound up being transplanted to R-Space's Earth.

See also: Dimension