Ok, so I am a little late posting as usual, but here is my favorite bubble. It also happens to be in one of my favorite insulators. This is a CD 1003 green glass block. The bubble starts at the flat part of the very top of the insulator (where it is open), goes down the side and covers a good part of the bottom. The bubble caused a bulge up into the wire groove and the wire had to rest on top of the bump.