Spark plug issue

[Merk RR]

97 4runner with 245k miles

Started misfiring so I checked the plugs and found the center electrode missing from one of the plugs.

These are NGK plugs, is this going to damage my engine? I tried seeing if I could get it with a magnet but with no luck..

 

[Bumbo]

Wow... finding that would irritate the hell out of me too... not knowing if its still in there of its vanished into thin air already...

I dont know what the correct answer is, but if you have loose debris in there, it cant be good, but it might have left though one of the valves and be somewhere else already.

I really have no idea.

If you felt like breaking one of the other electrodes off another plug, you might want to test if its even magnetic...