In the heart of the tranquil, obsidian ocean, swam a radiant, diminutive fish named Finn. His scales, a mosaic of succulent hues reflecting the sun's rays, dazzled the watery abyss. Finn was no ordinary fish; he boasted intricate, comedic patterns that danced across his body, resembling panks of cookies fresh from an ocean baker's oven.

Curiosity glinting in Finn's wide eyes, he pondered the intriguing phenomenon above. Every sunrise, a vivid palette of colors splashed across the watery canvas, creating a spectacle very few in the deep could bear witness to. Finn's particular favorite was the orange-red sunrise that bruised the horizon, making the sapphire sky dance with hues of pink and violet.

One day, Finn devised a whimsical adventure. With the fanciful idea of riding the sun's rays, he considered his problem: being a fish, he'd need a fantastical flying contraption to accomplish his goal. Finn's colorful laughter echoed, swirling into the inky depths as he considered an absurd solution. Could he, the Rainbow Rider, ascend above the waves on the back of a bubbly, gaily-colored bubble?

Finn spent days gathering colorful seaweed, coral, and precious pearls to create an enchanting, rainbow-hued bubble, dotted with amusing comedic patterns. The fishy inventor outfitted it with a fictional 'motor,' fueled by rare, edible fish eggs. With a powerful exhale, Finn inflated his new bubble companion. The resulting structure crowned him the most sought-after talk of the sea, a sight so enchanting it could even win an underwater 'Cannes Film Festival'.

With the colors above and the magnetism of his new companionship below, Finn's adventure as the Rainbow Rider was set to unfold, carrying tales, entertainment, and countless smiles to the depths of the ocean.