What is The Dead Hand?

The Dead Hand is one of the many dangers of the swamp, this being is a hand that latches onto a living hand, and if not stopped with break the hand, rip it off and continue up the arm until it's victim is dead. Briony is able to fend off the Hand when it attacks her, but not before it breaks all the bones in her right hand. She also gets it away from Eldric, but not before it takes off his hand.