Envision a dynamic, expressive charcoal sketch depicting a lion mid-roar, its mane flowing wildly in a phantom wind. The sketch style should be loose yet incredibly detailed, focusing on the muscle tension in the lion's face and neck, and the texture of its fur. Dramatic shadows and highlights, achieved through varied pressure and smudging, will emphasize the creature's ferocity and grace. The background should be minimal, perhaps suggesting a savanna, allowing the lion's powerful form to dominate the composition. This piece should feel visceral and alive, capturing a fleeting moment of pure, untamed strength.