A colourful pet crab called Xia-Xia is scuttling off shelves in the run up to Christmas, with one of the plastic crustaceans being sold every seven seconds in the US.

The playful crabs, pronounced Shah-Shah, come with detachable mix-and-match shells, and can scamper with lifelike alacrity. A separate mini-crab hitches a ride on the back of its mollusc mate.

Scheduled to reach British shores in January, toy company Character Options has arranged for a one-off shipment to make it way onto shelves in time for Christmas. However only 150,000 are going on sale, leading to fears that some wee nippers may fail to get their claws on the popular crab.

Panicking parents have been snapping up the toy online in the US, paying up to double its recommended retail price of £9.99. Accessories for the toy cost up to £12.99

The toys’ manufacturer, Cepia, are pinching themselves as this will be their second success after Go Go Hamsters, a huge hit in 2009. The crazy crabs are capering off shelves 20 per cent faster.

Paul Mitchell, of Toy R Us, told the Sun: “If the last few days in the US are anything to go by, Xia-Xia is going to be a big hit this Christmas”.