"Moses stretched out his hand over the sea, and at daybreak the sea went back to its place."

This mod patches bug MC-278019 that makes sea level in superflat worlds begin at y-level -63 and manually sets the sea level to begin at y-level 63. This fixes the need to be below y-level -63 to stop phantoms spawning, and allows natural aquatic mob generation including nautiluses.

Check out the video below that includes this mod in action.

[Video coming soon...]