Scrabsters were a revolting and destructive type of sky-vermin. They infested sky ships and ate the cargo; in the worst scrabster infestations entire cargoes could be devoured. Scrabsters were gelatinous, but they were protected beneath their knobbly, opaque, bleached shell. Fat scrabtsters started to ooze out of their shells. Scrabsters had twelve spindly legs, three clawed mandibles, and a whiplash tail. Their two eyes were black and beady, and were found on the end of thin stalks. Their young were contained within an egg sac that hung beneath their shell, and when they were born the empty egg sac remained there.