Help with horrible noise pleas

To me, it looks like a piece of nylon string that may have come up from the road and was tied to something metallic. It wrapped itself around the pulley. The metallic item came off as you turned the car ripping the nylon string.

If this is the case, you came off lucky.

No, it's a frayed belt.

Hi two things I thought of,

The clanging noise was the metal retainer band has fallen of the back box-very common

or ,has the alternator closing panel slipped onto the belt or fell off completely -the original ones were made of something
like paper mache...

mike