Big metal piece in oil pan

So my head gasket recently blew up there was milky thick yellow stuff in coolant system in oil pan and pretty much everywhere in the engine. Basically there was no oil what so ever there was only thick yellow liquid. I replaced my head gasket and timing today and found no damage on the head (as inspected by my naked eyes). But I also wanted to change oil pump chain so I dropped the oil pan and I found a big metal piece. I will include picture of that piece. There was no check engine light when head gasket blew and the did not overheat. The was running fine. The only warning light I got was low coolant so that’s when I checked dipstick and found out that there is water in the oil. Could please tell me where does this piece of metal belongs in the engine. This was only metal piece I found. There was no shaving of anything else. It’s a pretty big metal piece. Please explain if this something serious or not worry about?