Source: Xanathar's Guide to Everything

Wondrous item, common (requires attunement)

While you are playing this musical instrument, you can create harmless, illusory visual effects within a 5-foot-radius sphere centered on the instrument. If you are a bard, the radius increases to 15 feet. Sample visual effects include luminous musical notes, a spectral dancer, butterflies, and gently falling snow. The magical effects have neither substance nor sound, and they are obviously illusory. The effects end when you stop playing.