This is an entity who inhabits the world between worlds. It lives suspended within our material plane and is only visible to us in a certain light at a certain angle, and then only if we are in a very particular frame of mind... alert but still-minded.
It is nearly impossible to study these phantoms, although we have tried. Data is difficult to gather due to the mental emptiness that is necessary in order to perceive the space within space in which these beings slip and slide.
Perhaps there are mysteries that are best left obscure. Perhaps we are fortunate to have caught even a glimpse of this apparition. Perhaps the most important thing we can learn from this is that as much as we study and investigate creation, we will never understand it's entirety. This is a humbling fact, and it keeps us in our place.