Oscar Obsidian tells the story of his long life journey, starting as a marble rock named Matthew Marble that was shattered by another falling rock. He was then flooded by rainstorm waters named Willy Water down mountains and rivers to the ocean. Plate tectonics pushed him into the mantle where he melted into magma called Marcus Magma and rose to the surface, cooling and hardening into the igneous rock Oscar Obsidian.