Seen it on GSP Island in the past. Dont care about GSP, so in return don't care about this thing. However, I saw it on my rocks tonight so now I do care. Have only saw it ay night, seems to be a stringy thing, had to use tweezers and work it off the GSP, and more is still on there was super resilient to not come off. It is like a yellowish, green with black as seen in the photo. Never seen this thing/stuff before.