The wires in Project West Ford weighed something like 40 micrograms, with a diameter in the low tens of micrometers. They don’t really fit the criteria of what’s being discussed here - they would not do significant damage to other satellites, and while they could reenter the atmosphere and hit a person, you probably wouldn’t even feel it.
…and for those unfamiliar with this fun project, the idea was to provide a radio relay system that wasn’t easily disabled by an enemy. This was before communications satellites were common.
