Knocking briefly then gone?

Today I drove my MS6 a lot and then parked it for 10 min. When I started it up I heard a knocking sound. Not super loud. Then I drove 10ft just to see what it did and the knocking was completely gone and didn’t come back for the next 2 hours of driving. In the brief time I heard it it sounded a lot like rod knock, but I’m not sure.

I am overdue for an oil change (drove an unexpected amount the last few weeks) but the oil isn’t low.

Any thoughts? Can rod knock show up out of the blue for 8 seconds and then disappear? What else could it be?