Bad hair day
Notomithrax (Decorator Crab) species, possibly Notomithrax ursus found on the Tessellated Pavement, Eaglehawk Neck, Tasmania. This guy is interesting in comparison to the first specimen I found at Goat Beach as he's only really weeded up the top half of his carpace. This reveals the hairs into which the crab weaves it's camouflage.
UPDATE: I initially though this was Naxia tumida but according to Australian Marine Life (G.J. Edgar) this is actually a Notomithrax species.