Slicing, piercing
Free falling then gone
Constant movement, never ceasing
Ever downward, never up
Blanketing, smothering
Save me now before I die
Trapped in this blinding white
And the lights are forever gone
And the lights are forever gone

Although the title gives it away, try to think of the answer to this poem anyways.  It doesn't seem like what it would be at first glance.