A Short Cut to Mushrooms
Not far from the road-meeting they came on the huge hulk of a tree:
it was still alive and had leaves on the small branches
that it had put out round the broken stumps of its long-fallen limbs;
but it was hollow, and could be entered by a great crack
on the side away from the road.
The hobbits crept inside,
and sat there upon a floor of old leaves and decayed wood.
Frodo: "Get off the road! Quick!"
Round the corner came a black horse, no hobbit-pony but a full-sized horse;
and on it sat a large man, who seemed to crouch in the saddle,
wrapped in a great black cloak and hood,
so that only his boots in the high stirrups showed below;
his face was shadowed and invisible.
When it reached the tree and was level with Frodo the horse stopped.
The riding figure sat quite still with its head bowed, as if listening.
From inside the hood came a noise as of someone sniffing
to catch an elusive scent;
the head turned from side to side of the road.
Sam: "Be quiet!"
A long-drawn wail came down the wind,
like the cry of some evil and lonely creature.
It rose and fell, and ended on a high piercing note.
Even as they sat and stood, as if suddenly frozen,
it was answered by another cry, fainter and further off,
but no less chilling to the blood.
(from: The Fellowship of the Ring, pages 109, 111, 128)