Barbed Irons

Concise Bible Dictionary:

Harpoons
Irons shaped like a harpoon, that will enter the flesh easily but which cannot be withdrawn. God, to show His wisdom and power to Job, speaks of the leviathan, or crocodile, into which barbed irons have no entrance (Job 41:77Canst thou fill his skin with barbed irons? or his head with fish spears? (Job 41:7)).