These Sponge Isopods are actually fairly common. But they are so small, do not move that much and so are overlooked by most divers.
when you can actually see them, they are fascinating creature. In this video you first get an idea of their size. when I get close-up you can start to see some amazing features that are just impossible to normal see.
If you look closely, the first weird thing is their double-jointed legs. They seem to be able to bend the first set of three (out of seven) legs up, and keep stroking their backs. I wonder of they are taking small bits from the sponge and placing on their bodies, as the texture almost seems to be sponge-like
You can then notice the top Isopod has eggs!! You can see a white mass under it's body. The eggs must truly be tiny.
And finally, you can see there are some even tinier creatures which are white that are crawling around too. I don't think these are juveniles, as there are also very small orange isopods around too.