This is a vampire crab. With its purple body, orange pincers and piercing pale eyes, it’s a nightmarish vision. And a crab that’s also a vampire? Days out at the beach will never be the same… You may not have heard of a vampire crab, though it’s a species popular with aquarists – in fact, illegal over-collection for the pet trade is a real threat to the species. As alarming as it looks, this...