Quoted from KarlKohler:I have one on the playfield of my MB. I am trying to learn what the markings represent. The right side of the bubble is between the first and second mark. The second mark looks like it is slightly wider than the other 5 marks. There are six marks total. Any feedback is welcome!
It's explained on page 1-4 of your manual.
If you don't have a manual, you can download one here under the documentation header:
http://www.ipdb.org/search.pl?any=monster+bash&search=Search+Database&searchtype=quick