The human body and its reflection are not the same beneath their skin. 

The image contained within a silvered mirror’s surface seems identical to its observer, but this semblance is usually only a few photons thick. Beneath the opaque barriers of the double’s visible flesh, a candle burns within a cage of transparent ribs, reinforcing the lifelike coloration of the illusion beyond. It is held in place by the long, glass candlestick of the spine, which refracts the firelight into sinuous rays of vital crimson.

These prismatic vertebrae are not unique in their properties; in fact, every bone within the double’s skeleton contains all the information required to project the rest of its body’s interior into place. The holographic etchings that line their curvature reveal the blueprints of a cube-shaped liver, pyramidal lungs, and a whale’s-length digestive tract that winds through itself like a Klein bottle. As soon as these structures catch a glimmer of the flickering flame, the rest of the reflection’s body is filled with anatomical complexity. Every organ within is active and alive, animated by subtle motions in the candle’s smoke.

Of course, this other being and its anatomy are products of the imagination- but only partially so. While the space seen within a mirror is a form of inner space, it is, in fact, inner space projected into the outside world. Everything seen beyond its surface exists in superposition with physical matter. Through this loophole, the unconscious mind is able to take form in the outside world, though its true nature remains hidden behind a veil of light.

Despite this obfuscation, a committed and perceptive observer can see through this mask, into the truth that lies beyond the glass. Should one gaze into a mirror in a completely darkened room, after a long enough period of focus, the inner self will reveal its true face.

And all that's without even plugging the mirror in.

Due to a technicality, Medusa was never able to see her inner self.

This process is part of what grants Bloody Mary her body.

Be careful: confusing reflections and doppelgängers could cost you dearly.