The other shells around them begin pulsing and the ground is now rumbling enough for those without whale echo-based hearing to feel and hear. The shell sigil on the ground seems to shift, twisting around and down.

The water get's rough a moment, buffeting them around and sand rises from the sea bed making the water murky.

But it settles and when it does they can see a spiral staircase, leading downwards into the dark sand below.