The Astral Plane is a metaphysical plane of existence pertaining to the mind or spirit that is accessed by psychic mutants or other psionic means. Psychics can project their consciousness, sometimes even their physical bodies, into the realm, while truly powerful ones can actually manipulate the realm with their minds and perform feats such as turning their limbs into weapons, growing in height, or creating dream-like illusions. The astral plane is also sometimes called astral dimension, dream dimension, astral realm, or spirit world.
- When in the Astral Plane, Apocalypse grows immensely in size. This is a reference to the comics in which it was one of his many abilities.