A club made of straw would not hurt him, and a club made of wood would not hurt him. This can be translated in active form. AT: "He thinks of clubs as if they were straw" (See: [[rc://en/ta/man/translate/figs-activepassive]])
The person throwing the spear hopes that the spear will kill Leviathan, but the writer speaks as if Leviathan knows the spear will not kill him and so laughs. (See: [[rc://en/ta/man/translate/figs-personification]])
Just as a threshing sledge goes over grain on a threshing floor and turns it to powder, so Leviathan's tail leaves a trail in the mud as he wags it when he walks. (See: [[rc://en/ta/man/translate/figs-simile]])