Mysterious piece found in oil pan of cummins motor.

I was helping a friend do a service on a 04 T800 mixer. On the drain plug I found what looks to be a piece of cast iron. None of us here at the shop nor the two Cummins mechanics with "30 years a piece" can figure out where it came from, the motor is a Cummins ism. Any help would be much appreciated, even a place to start looking. Thank you. View attachment 180138 View attachment 180139 View attachment 180140 View attachment 180141

Mysterious piece found in oil pan of cummins motor.