Create a premium children's coloring game app icon featuring an adorable baby unicorn with oversized glossy eyes, thick smooth black outlines, and a joyful smile. The unicorn is mostly black-and-white coloring-book line art while a giant glossy blue marker enters diagonally from the top-right, releasing a spectacular rainbow paint splash toward the character. The colorful splash dominates the center of the composition with vibrant liquid paint, glossy droplets, magical sparkles, flowing ribbons of color, and soft glowing effects. The paint begins transforming the unicorn into vivid candy colors exactly where it lands. The unicorn fills about 60% of the canvas, while the oversized paint splash fills nearly 30%, creating a dynamic action scene. Render in a polished Pixar-quality 3D cartoon style with premium toy-like materials, bright studio lighting, smooth gradients, thick readable outlines, a pure white background, and exceptional readability at small app icon sizes. No text, no borders, no clutter.