So I was helping my friend change the spark plugs on his car and I encountered this
http://i1055.photobucket.com/albums/...Photo00851.jpg Sorry if the picture is a bit blurry
We've replaced all of the spark plugs except this one. I have never seen this before. The spark plug is round for some reason instead of being a hexagon. The other plugs that we removed were 5/8. When I put the socket in to remove this spark plug, it doesn't go down all the way like the rest of the plugs. I Searched every where but i can't seem to find anything on this. All help will be appreciated.