broken spark plug

Never experienced before! Today lovely weather so I'm going for a nice ride, hmm doesn't start well and runs on three pips but then good. Still on the way hmm, at home I looked at spark plugs anyway, No. 3 the cap is very loose...WTF! . I have no idea how this is possible because I am always very careful with turning in and out. Anyway, put in new spark plug and machine runs fine again! Spark plug is a year old, has anyone here experienced this before?
Willem

Never ever seen a broken spark plug ceramic like this. Looks like you have a new "friend" in the neighborhood, so be alert!

Another member here had someone break their spark plug and take it.
Used for a pipe or something to smoke drugs.
Was an end plug though, not #3.

I've read that the broken ceramic can be used to break car window. Perhaps someone prepping for a smash & grab?

Well, its strange, my bike was about 60 minutes on the street in front of my house. So yes its possible some idiot crushed the plug. Anyway, I changed the plug, bike runs well and the Z is save in the garage now. 

wrote:

I've read that the broken ceramic can be used to break car window. Perhaps someone prepping for a smash & grab?
That's what my son also mentioned 
 

I've come out to find plug wires removed.  Never underestimate the troublemakers in the hood.