Redeye Sponge Crab

Found with a sponge cap on their heads, that they have cut and shaped to fit, usually stationary during the day, under their caps, out at night foraging for food, over coral and rocky reefs.

Brachyura crabs are considered true crabs, they have a short abdomen, 4 walking legs and a pair of clawed arms at the front.
Many thousands of species live worldwide in sea water, fresh water and on land.