When it detects sound, your tree lights up and sings Christmas songs! When the sensor detects sound, it plays three random Christmas songs. At the same time, the lights around star light up and flash in a colorful, slow-motion manner. Note: This tree star model does not include a light string. When someone walks around and speaks loudly, your tree star sings! When a present is removed from under your living room tree, star recognizes it, lights up, and plays Christmas songs!