YES!!! i was aslo wondering about this! luckily, it was only on the backs of a couple of my LRs, but its was weird. i was scared to touch it, incase it was slimy or it was gonna pop and like let out a million little baby somethings that would attack my tank... because it kinda looked like and egg case.... you know? so anyways, i have no idea what it is, but i hope you get an answer.
