A traditional Intaki musical instrument, the clacker consists of two flat pieces of lightweight material, loosely bound at one edge. When that end is held and the other end swung forward, the instrument produces a sharp clashing sound.
Given the scarcity of wood in space, the instrument today is often made from plastic or other polymer variants. More complex variants have lights or chemicals inset in the material that can make the clackers do anything from reflecting light to taking on an eerie glow, or even emitting sparks.
It's not at all uncommon for older siblings to frighten their younger relatives by sneaking up at them in the dark of night, rattling their clackers like some red-eyed beast of myth snapping its jaws.