A Rolling Intruder

A sudden low hum rattled across the floorboards. I tracked the vibration directly to the gap beneath the couch. Something was stirring in the shadows. I dropped my front stance, steadying my paws on the flat weave of the rug. A faint click echoed, followed by a light plastic tap. Out rolled a forgotten green tennis ball, propelled by a morning draft. It wobbled three inches, slowed, and tapped against my left paw. I pressed my snout to the felt surface. Familiar wool scent, stale dust, no hostile pulse. The boundary held. I nudged it back against the sofa skirt to keep the lane clear.