Ether
According to the wave theory of light, ether is a material that permeates all space and transmits all waves. Thus, ether is a medium. An invisible medium which like all matter can be neither created nor destroyed. Though untouchable, unperceivable, and formless, ether is everywhere. What happens when you take a step into a world where ether is material? What happens when it becomes too dense, too concentrated? Thus explored is ether's reality. The invisible, visible.