The Spider Decorator Crab (Camposcia retusa) is also known as the Blunt Decorator Crab, the Velcro Crab and the Tarantula Crab. They camouflage themselves by placing pieces of organic matter from their immediate environment on themselves and generally unless they move it is very difficult to see them. They rarely go onto a background that does not camouflage them. This one has climbed a barrel sponge and is easy to see. It is missing a leg but this will probably grow back on its next shell change. This specimen has clipped pieces off of a flip flop shoe ( The Black and Blue pieces) and attached them to its self as camouflage.
Every year many thousands of flip flops are washed ashore on the East African coast , these are brought in from the east on the South Equatorial current. The currents circulate up the west Australian coast, up past Indonesia and then circulate back to Africa and bring large amounts of floating debris onto the beaches.
Such is the volume of flip flops floating from the east that in Kenya an entire industry has sprung up. Just one company recycles tons of flip flops off the beaches in Kenya. You can read about it here. https://oceansole.com/