The Crush Claw can paralyze victims as well as crushing them. There is no metal left unaffected by it.
The Crush Claw is not known to have had another owner before Thunder. It was used in numerous villainous acts before being confiscated by Hero Factory.
The piece Crush Claw refers to a part of the whole weapon, not the weapon itself. The Crush Claw weapon includes three of these pieces.