Francesco Tacchini, Julinka Ebhardt, and Will Yates-Johnson wanted to explore "transitional public spaces," like stairs, tunnels, and elevators through acoustics.
What they came up with is Space Replay, a dark floating ball that records and echos eerie footsteps and conversations. The hovering orb is actually a latex balloon filled helium and electronic components that handle sound. The sphere, which weighs about 4.2 ounces, naturally follows the air currents caused by anything that moves past it.
Watch the spooky thing go in this video.