[Fallen Angel]

All that was on the plug itself? Possible that it may be a leak from the valve cover?

It would also suffice to say, that plug is in need of replacement.

 

[Fallen Angel]

Take a look inside the hole for the plug. See if there is any oil coming from where the valve cover gasket meets the head. Very common leak on older engines. Can also cause problems running with that stuff in with the spark plug.