Insanity

Far and deep below the ground,
A sinister creature can be found.
Hideous and frightening its facial expression,
Flesh and blood its prime obsession.
Hark and you will hear him calling,
A leaf from a tree falling, falling.
Look to the east, there wakes that beast.
In his hand, the entrails and organs of a man.
He now stands before you, but how he adores you.
But in the blink of an eye, he did fly.
And he is not there but where.
Is this a dream, what could it mean?