Answer:
In a tunnel of darkness lies a beast or iron. It can only attack when pulled back. What is it?
If a man carries my burden they will get crushed to death. Though not rich I leave silver in my track.
I am a kind of coat that can only be put on when wet.
I am black white and read all over.
I am quick when I'm thin. I am slow when I'm fat. Wind is my worst nightmare. What am I?
Whoever made me don't want me. Whoever bought me don't need me. Whoever use me don't know me.