They're tiny, active, and the same color as their background. Three pairs of legs in back, an inchworming (though crustacean-jointed) motion in the middle, and what looked like a pair of legs and a spike in the front. A little time with the search engine speaks of two pairs of legs in front, and another mentions three antennae, and, well, there are plenty of species. Most were about 1 cm. A 2-cm one climbed onto my glove while I was examining the float that I photographed, which they had ridden in on (their camouflaged activity was inconspicuous enough that I didn't notice them at first), but it blew away in the wind before I had a chance to get a good look. That was an awkward sentence. One source said that some species can actively take on the background color, though I don't know whether these guys could. I don't know whether they are clear and eat the orange seaweed stuff or what. I did at least see that some are filter feeders, some catch tinier things to eat, etc. Maybe I'll find a resource in the library. Anyway, I know you haven't read this far, hypothetical reader.
Someone got the exposure very wrong (I already have pictures of everything that's around here to see, so I'm awfully out of practice), but I somehow liked it anyway.