Mirage at Nightfall

As I was in the undergrowth
The sweat fell off my brow,
And onto the cold black steel
That I clenched in my palms.
So many senses were alert;
More than had ever existed!
Night fell within moments
Over the dense and foggy woods.
What was that sound?
The crunching of leaves?
Or maybe it was only
My imagination!
Then I saw form a distance;
My quarry.
He stood against the purple sky;
A rifle positioned on his shoulder;
As he moved silently through the fog.
I let go of my breath;
And shot my quarry down.

But how can a bullet
Shoot down a tree?!