Cooper woke up with a cheer, for the beach day was here. Papa Eric packed the car, the beach wasn't far. They brought buckets and spades, and lemonade in shades. Off to the beach, they went, with a joyful intent.

Cooper built castles so grand, with Papa Eric lending a hand. They dug moats deep and wide, as the waves crashed by their side. The sun shone bright and high, as seagulls soared in the sky.

Suddenly, a splash was heard, louder than any bird. Cooper turned to see, what the splash could be. A fin rose from the sea, big and wide as could be. Papa Eric said, 'Don't fear, let's go and see what's here.'

They walked to the water's edge, past the sandy ledge. There, a whale shark did appear, gentle and clear. Cooper's eyes grew wide, as the whale shark swam by his side. 'Hello, friend!' Cooper said, and the whale shark nodded its head.

The whale shark offered a ride, and Cooper climbed on with pride. Papa Eric joined in too, as they dove into the blue. They saw fish of every hue, and coral gardens too. The underwater world was bright, filled with colors and light.

Deep in the ocean's heart, they found a treasure chart. Cooper followed the map's trail, guided by the whale shark's tail. To a chest, they did arrive, filled with jewels that seemed alive. 'This is for you,' the whale shark said, 'A gift for the life you've led.'

As the sun began to set, it was time to leave, they met. Cooper hugged the whale shark tight, under the fading light. 'Thank you for the ride,' Cooper said with pride. The whale shark waved goodbye, with a splash and a sigh.

Back home, they told the tale, of the whale shark and the treasure trail. Papa Eric and Cooper smiled, remembering the adventure wild. They dreamed of the ocean deep, as they drifted off to sleep. The end of a magical day, in every possible way.