Mudcrab

Scylla serrata (often called mud crab or mangrove crab, although both terms are highly ambiguous, as well as black crab) is an economically important crab species found in the estuaries and mangroves of Africa, Australia and Asia. In their most common form, the shell colour varies from a deep, mottled green to very dark brown. These crabs are highly cannibalistic in nature and when another crab undergoes moulting the hard shelled ones attack the moulting crabs and devour them. The females can give birth to 1 million offspring which can grow up to 3.5 kilograms (7.7 lb) in size and have a shell width of up to 24 centimetres (9.4 in) wide. (ref Wikipedia)