noun - a person with the ability to pass through walls with or without the aid of technological advancements.

See also:
transmuration - {noun} the general term for walking through walls.
transmuring - {verb} the act of passing through walls
to transmure - {verb} to pass through walls.

Briefly, "the realization that each random passerby is living a life as vivid and complex as your own." Originally from the Dictionary of Obscure Sorrows, which has a lot more beautiful neologism definitions like this you might enjoy.