'Sea monster' in the Bible

Am I the sea, or a sea monster, that you keep watching me?

By his power he disturbs the sea; and with his skill he shatters the sea monster.

"Awake! Awake! Clothe yourself with strength, you arm of the LORD! Awake, as in days gone by, as in generations of long ago. Was it not you who split apart Rehob, who pierced that sea monster through?