Spark plug removal
 

Getting ready to change spark plugs and found that the #4 spark plug has a rubber boot at he base that prevents me from getting a grip with the plug wrench. Any Ideas? and what is this for?

Not sure exactly what you are talking about. Rubber boot down in the plug hole? Or covering the plug?

Spark plug removal
 

It is at the base of the spark plug

Whatever it is, it isn't supposed to be in there.

Could be the rubber padding that is inside of some plug sockets.

Maybe it came out of the previous owner's socket and stuck on the plug.

that would be my guess, if you have any long hooks or picks that could get down there you could probably get it out

+1 to the rubber o-ring like material not being in the right place.

I'd try a wire coat hanger, meticulously and carefully fishing it out. Or a spark plug socket without the o-ring and seeing if you can fish it out. Good luck!

(yeah a pick set would work too :))

Spray some CRC or fine penetrating oil onto plug then try to gently remove using all the methods above ,,wire etc.
If you can get it to move up and out the oil will lubricate and help it move off .
It must be the water sealing from the plug socket ....as mentioned above .
Make sure you replace it if its from the socket as its there for a reason ......a good reason ...........waterproofing

Take Two ..Just a thought ,it could be the grip rubber from spark plug wrench that's been used before and the rubber has come out and stuck on the plug insulation .Happened to me on a motorbike .