The Hollow Sound

I marched off the soft rug onto cold, smooth floorboards. Right ahead stood a big wooden sofa leg. Perfect. I leaned down and tapped it with my domed head. Thunk! A dull click answered back. Chirp! But right next to it was an upside-down tin lid left by a mug. I backed up two steps, lowered my nose, and bumped the metal rim with all my weight. Ting-clang! The loud rattle echoed right under the couch. I held very still, front claws gripping the floor, waiting to see if it would ring again.