Transparency.

It's reached that one point
Where I can look in the mirror
Instead of seeing myself
The wall behind shows up clearer
It's the way I've come to see me
And it's mimicking the way you do
I'm not even here anymore
And then you'll just walk through
Transparent as glass
With these thoughts beating me down
While you're highly living opaque life
Complete with throne and crown
Maybe one day I'll walk through you
You'll feel the oncoming rush of air
That haunting breeze that chills your bones
The only hint that I was there