This nut was found in the #4 cylinder head, #7 valve (2nd closest to throttle body/plenum) partially wrapped around the guide and stem.

I have not taken apart the intake manifold from the throttle body to head since I owned the car, so this did not come from me. As such, it has been doing this for at least 1400 miles. It appears to be well cleaned and lubricated by the fuel.

Also, being gold/bronze in color, this explains the shiny metal oil sparkles I recently discovered.