I believe it has knobbly knees and a bulbous nose.
And sparse fly away hair and ears of cob.
Its' mouth is grim with pointed rotten teeth
and a mole upon the chin with a white hair
pointed in. Its' feet are bare and black with filth.
The legs and arms are spindles of bone.
Its' hands are gnarled but strong for pitching stones
at us who get too near.

But where does it live, this filthy vile thing?
Why of course, under the bridge of the babbling brook.
Where the grass and flowers are young and sweet.
And when I get too close the air turns foul with the stench
of its stinking breath.

You ask for what purpose does it exist and what do
you call this abomination of sight and smell?
The purpose of it is to make life miserable for
you and me. It taunts, it yells words of ill, it snarls
and grimaces at our discomfort. We back away, as we find
no pleasure in its presence so ugly.
What do I call this thing, this smelly, ugly thing?
Why a troll of course, what else could it be?
A troll you see is to be seen but not to belong.
A troll is a vile, ugly, smelly and filthy thing.
So don't worry, its under the bridge and there shall it
stay. It has been bound by a very strong rope and shan't
be free to bother you or me.