It was a good hiding place.
No-one would find him here, and safe in the darkness, he settled down to sleep.
When he awoke, the landscape had changed and he saw other doorways into tunnels that had been hidden by the tide.
His own cavern was no longer footed by water, and he tentatively put his feet down from his rocky bed onto the gritted floor fully expecting to sink up to his waist.
On wobbly legs he walked out into daylight, marvelling at the freshness of the air, the warmth of the sun and crisp clean colours of the shoreline.