You definitly are missing part of the drain plug and it is trash. Hope some of that didn't get to your oil pump causing the noise on start up. Check the threads in the oil pan for damage. You may need to run a tap through the tthreads to clean them up. You may try to bend a wire and fish it through the hole and seeif you can pull back any metal from the plug or maybe get a small magnet in there. When I ran a tap to clean up my threads I poured back my old oil and let it drain through to clean out any metal from the tap. Also look at your oil filter carefully for any metal that might have been pumped to it. Good Luck.