Trypaea

Trypaea australiensis, known as the (marine) yabby or ghost nippers in Australia sometimes known as one arm bandits due to their occasional abnormally large arm, and as the Australian ghost shrimp elsewhere, is a common species of mud shrimp in south-eastern Australia, the only species in the genus Trypaea. T. australiensis is a popular bait used live or frozen by Australians targeting a range of species. It grows to a length of 6 centimetres (2.4 in) and lives in burrows in mudflats or sandbanks, especially in or near estuaries.