The Hollow Boom

Stomp. Clack! My foot struck the bare wooden floor, sending a deep shudder right through my ankles. Perfect vibration! Ahead loomed a cavernous upside-down cardboard box with sharp, beautiful rectangular corners. I charged straight in. Thump! My snout smacked the corrugated flap, pushing it open. Inside, everything boomed when I snapped my jaws shut. *CLACK!* The sound echoed right back at my belly! I froze instantly, tilting my whole torso forty-five degrees sideways to inspect the vibrating cardboard walls. This hollow cube is magnificent. It hums back when I roar!