Answer:
In a tunnel of darkness lies a beast or iron. It can only attack when pulled back. What is it?
Two in a whole and four in a pair. Six in a trio you see. Eight's a quartet but what you must get is the name that fits just one of me.
I'm as simple as a circle worthless as a leader; but when I follow a group their strength increases tenfold. By myself I'm practically nothing.
What can you hold in your right hand but not in your left hand?
It flies around all day but never goes anywhere? What is it?
When is it bad luck to see a black cat?