Sometimes I am very small
But sometimes even tall
My name is sometimes spoken with a humans name
but I am not an human at all
you can throw me but not If I am too heavy
And even if I'm very light I cannot walk away
Once I was a part of a union
But now I am a one-man-Army seeking for a revolution
I was cut and separated from my Family
But you can pick your family and climb on me

I hope this not too heavy for you ;)

EDIT: I think now it's a little bit easier and more precise ;)