Marlin Harpoon

This was a unique, sentient weapon wielded by Isari Funato. It was later destroyed by Misuno when it attempted to attack Chōjūrō.

Overview
Originally belonging to Araumi, at some point he gave it to his eldest son. While dormant, it normally appears as a harpoon with a marlin-shaped skeleton akin to a pike on top of a long pole with a long rope. Upon awakening, it becomes enlarged and more akin to a full-bodied marlin, metallic in structure. In either form, it is easily capable of piercing through and destroying rock and steel. When transformed, it also has the ability to freely fly though the air in the same manner as a fish would swim. It is able to quickly consume chakra on contact — even from complex techniques like the Rasengan — and will take a liking to particular chakra. While it obeys Isari, because it was given to him by his father, Araumi's commands override his, to the point that it would kill Isari once Araumi declared that even relatives would not be spared if they stood in his way.