Perhaps, a selkie.

On the beach this morning sand. The sea, calm, wrinkled only slightly by the wind. Stone, carved by the sea, sand, wind. Light washing all and then with the rain came a rainbow, at first feint, then clearer in the darkening of the light. The bow seemed to hold back the curve of dark cloud.

Like so much magic the colours grew from sea to sky and echoed in the mirrored light reflecting from the sand, until the rainstorm passed and only a smur of light fell down and struck the north end of the beach, light kissing sand.

If you look with care you can see the rainbow touch the beach in the bottom right corner.

And on the beach this evening; again sand, sea, stone, but this time all stripped bare of colour by the moonlight. Stars reflected in the mirrored surface of the wet beach and we walked as if suspended between heaven and earth. Stars above, and infinite space and stars beneath and all the while the moon threw a shawl of silvered clouds to roof our heads.

Once, when I walked in the twilight morning, just as the world was coming to light I saw a shape beside the sea. 

A rock? 

It was dark. 

But no, a movement. Perhaps a trick of the half-light, but no, there again the darkness moved. I stood, alone in the morning world and watched. A seal?
It moved up the silvered beach and then raised itself, stood tall and straight beside the foam edge of waves, still dark. It stretched up tall and elegant with grace, looked around.

I held my breath. 

I watched. 

And it must have sensed the watching for it dropped, elegant, back to the sand and then moved swiflty back to the sea. A wild thing. Until now I have kept it secret. Perhaps a selkie?