i got these things on my glass. they are like little 3/16 inch bubbles with little white things in them. i'm thinking eggs of some sort. starfish? stail? polychaete? they are flexible but very tough. i can use a scrubber pad over them and they don't break. also, for bleeding blue and wombat, i have coralline all over the glass. i'm leaving it because in a week or so this tank will be the fuge, and i want it there. also, a fish store guy tole me a good idea: if you want coralline, scrape it off a rock with a blade into the powerhead current and it will disperse everywhere. i don't know, sounds cool to me.