Wet spark plug on 2004 Ford F-150

When I went to change the plug in my 4.6 it was soaking wet with what appears to be motor oil. Where would this be coming from? I pulled it do to a "#6 cylinder misfire first 1000 rpm engine code."

Asked by for the 2004 Ford F-150
the valve cover seal for the tube is allowing oil into the plug hole contaminating the coil boot. i would replace the valve cover gasket, and the coil.

2 more answers , 3 more comments
this would be a bad valve cover gasket.
Thank you
Question: is the oil you see on the outside of the plug or on the inside (electrode)?
Mostly the outside, not sure if the electrode was wet, but it looked good.
In this case, Roy would be correct. It probably is a leaking valve cover unless oil was spilled at one time. Any liquid seems to find the way to the bottom of the spark plug area.