From Below

Somewhere down and deep below,
Dark and waiting silent,
Grinning wide and wizened so,
Wait the ancient giants.

Before light and laughing ones,
Lifted land from water,
Swam the aged and awful sons,
And the vicious daughter.

From the bed that birthed the sea,
Blind to all but hunger,
Came the titans tinged with glee,
To prey on those younger.

Still they plot and plan and wait,
Preying on the airless,
So rent and ripped is their fate,
Rightly, if they're careless.

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The above is a traditional Maritun poem that speaks of the creatures they believe to live upon the deepest parts of the ocean floor. While modern technology and magic allows for deep exploration, there are still parts of the ocean that have yet to be mapped.
The fear of the unknown is powerful enough for From Below to have been used in a recent human horror blockbuster. Marituns would be the first to say that it is not unknown to them - while they will not speak of it directly, they all seem to know in detail what it is that waits at the bottom of the ocean for those who would dare to dive too deeply.
This poem has supposedly been used as a children's song or even a lullaby in an effort by parents to instill a fear of staying beneath the surface too long and diving deeper than their air capacity allows. Analysts have suggested that the origins of the poem lie in a simple attempt to stop children from holding air for too long and diving so deeply that they cannot return to the surface in time to take a new lungful of air.
Again, Maritun have refuted this and state that there is no need to add fear to a truly terrifying subject.