What is "unspooling"

Usage examples of "unspooling".

During the slow march of summer days I was aware, as one is aware of a drum steadily beating across a lake, of something unspooling itself in the bodies of my campmates.

The farm boy did not stop at the high-striker, and I kept my spiel unspooling as I watched him pass by, and not ten minutes later I saw a second beast.