This was stuck to my oil drain plug magnet.
There was no shavings or glitter.
It has smooth rounded edges all around it so not sheared off.

-Niemand

 

I don't know specifically, but it looks like a retaining clip. I thought of valve springs first, but that part doesn't match. Google says it might be an outer retaining lip of a piston cooling nozzle (oil squirter), but I couldn't find an image of that part, so I can't verify it.

Regardless, this ain't good, man. I'm sorry.

 

I was hoping that it’s part of the oil pickup but I don’t have a spare one to examine.