Well, I've been a semi-lurker long enough on the forums, I suppose it's about time I contribute! Please give comments, criticism and ideas to expand my spark of innovativeness. The virgin planes detailed here can be used in any RPG world with planes, different dimensions or realities, etc. The basis here is on the D&D cosmology with its numerous planes, so I might also use some other D&D terminology in this post.
Planes, to those who study the subject, are all the different realities that make up the multiverse. The Material Plane is where the mortals' world exists, and the other planes are the sources of the cosmos' elements and energies, and, indeed, the home of the gods.
A virgin plane, also known as a newborn plane or growing plane, is a rare anomality in the multiverse. It's not known what spawns them, but cosmic turbulence or violent planar changes can cause a whole new plane to form. These planes, at first, are nondescript and blank, containing featureless land if, indeed, any land at all. If born from part of another plane, it might retain some features of its parent world.
But a virgin plane is merely growing at that point. It is reactive to the extreme, but at first it does little except expand. However, when material or organisms from another plane enters, the plane registers its appearance and begins to shape to either become like the intruder or to suit its needs. For instance, if a fire elemental was thrown by a random vortice into a virgin plane and nothing else entered the plane, it would eventually possibly become a carbon copy of the Plane of Fire.
I've only created various ideas for how the plane changes, and any other contributions would be welcome. Anyway, here are some:
-When any foreign object or creature enters the plane, if that plane has a surface, it could start to mimic the entered object when it would come in contact with the surface. If merely a hint of salt was for some strange reason teleported into the plane, the plane could slowly turn into an exclusively salty world. Of course, the effects of living creatures could be very bizarre.
-In a setting with magic, the plane reacts to magic used inside it, becoming like the magic used. The changes could be gradual and subtle or instantaneous. For example, a wizard casting a fireball might have to cast the spell multiple times before the sky would begin to take a red hue and the earth heave and rupture with growing heat. In another scenario, he might as well doom himself and any companions or enemies as the whole plane would explode in a violent supernova.
-The plane might react to a creature's needs, not its composition. A tired traveler might find the land turn soft and comfortable, easy to lay on and take a nap. A thirsty traveler could find water suddenly gushing out of the ground.
-The plane reacts to a creatures thoughts, wishes and wants. This is much like the scenario above. A person wishing for an apple might find a forest of apple trees sprouting around him (The Plane of Apples... I feel inspiration!), while someone recalling the bad case of flu he had would soon see the ground turn watery and pestilent around him.
The coolest effects on a virgin plane could be achieved when two or more foreign objects enter the plane, when the plane changes to suit all of the entered things. Battles, especially, could be very exciting. Imagine a troop of archers battling a cabal of mages on a virgin plane. Around the archers, the ground could grow arrows like flowers while the mages could find the area around them leaking magical energy all around. In the center of this chaos, the effects could combine into anything as wild as the sky raining magic arrows to all visible magic used having a pointy shape.
Eventually, as time passes, the virgin plane begins to stabilize and no longer changes. It might have become a full-fledged plane or merely a small demiplane, or it could have destroyed itself (imagine a person wishing death... bad move). From that point on, it is safe to travel to without the world changing wildly, though it could have turned into a very dangerous plane as time had passed.
Alrighty, that's my wondrous idea! It might be fully possible that someone has thought of this before, in which case I bow down and state that great minds think alike. However, I'd really like feedback about this and more interesting ideas. DMs could use virgin planes as an especially strange world to have the PCs adventure in, or he could use it as a way to create new worlds for his cosmology. Either way, I hope my idea was not a total waste of time for you fellas! =)