Job 41:30 in the King James Version
Sharp stones are under him: he spreadeth sharp pointed things upon the mire.
Context
29 Clubs are counted as stubble. He laughs at the rushing of the javelin.
30 His undersides are like sharp potsherds, leaving a trail in the mud like a threshing sledge.
31 He makes the deep to boil like a pot. He makes the sea like a pot of ointment.