This is one of the so called sponge crabs, with its rear legs articulating upward to hold something over itself. This species' choice of cover appears to be colonial tunicates, several different kinds of which are shown in the photos below. The first three photos show a crab hanging around the tunicate it is using for a hat, further helping it hide out. The crab itself varies in color. The name D. tridentata was suggested in the Facebook Crustacean Identification Group. Our crabs also look quite similar to the tunicate bearing Dromidiopsis lethrinusae in Ryanskiy (2020), although I'm not sure the shape of the rostrum matches a description in McLay (1993).
Created 9 August 2020
Updated 19 September 2021