I am very poor so I work on my house/SUV (2002 Ford Expedition) myself. Recent misfires had me changing coils and spark plugs. Well, everything is going fine until my extension comes off my socket wrench and falls into the spark plug hole. I was heart attack emotional. What are the chances of an extension and 8mm socket falling through the spark plug hole. I can not afford anything. Looking on line and watching videos, I decided to attempt to take the head gasket or whatever it's called to retrieve the socket. Not to mention that I really want some laughs when I tell you I turned the engine for like 10secs to see if it spit the extension out. I'm now stuck at the real big bolt that I have no wrench for. I was going to by-pass taking off the alternator but right now I'm just trying desperately to do something to make progress or admit defeat. Please tell me something I can do to get this extension with 8mm socket attached out of my cylinder.
Unfortunately as you say you have turned the engine over for 10 seconds you may have seriously damaged both the piston and cylinder head etc. Not to mention the bar with 8mm socket attached, which could be very bent and trapped now. This is unless you are really lucky and the socket bar are just lying sideways on top of the piston, and not been compressed at all.
If the socket and bar sound like they are still loose in the cylinder then you can try a magnet to remove them, but following that even if you are successful in removing them you will certainly then need to do some investigation as to whether the piston/cylinder/head/valves are damaged from having the bar and socket trapped in there following the 10 sec rotation.