Create a charming scene featuring a cute, round hedgehog with tiny, shiny eyes and spiky fur, huddled underneath a large, red-capped mushroom in a forest. The hedgehog is sheltering from gentle rain, with raindrops bouncing off the mushroom cap. In front of the hedgehog is a small, hand-painted wooden sign that reads 'Need buzz for shelter' in playful, slightly messy writing. The background should include soft, blurry trees, wet grass, and the faint hint of mist for a cozy, whimsical atmosphere.