The Japanese Nightingale

Origin
Long ago, the Emperor of China was befuddled to hear that despite his lavish palace, exquisite gardens, and beautiful towns, the thing of his country that everyone believed to be the best part was some, unknown (to him at least) bird called the Nightingale. This bird was said to have such a beautiful song, that anyone who passed it, whether a leisurely noble or a busy peasant, stopped to hear the Nightingale's voice. Immediately demanding this bird's presence in his own court, the Emperor was delighted and moved to find that all reports had been exactly true, that the little bird's voice was undoubtedly the most beautiful thing in all of his lands, and likely farther. The one fault that the wealthy Emperor found was the Nightingale's drab appearance, gray as it was. But he nevertheless had her stay in his palace, where she serenaded the court and it's guests for a long time.

However, the Japanese Emperor, who had heard of this phenomenal bird, for one reason or another, sent a gift to his Chinese neighbor, a mechanical nightingale encrusted with rubies and sapphires and diamonds and gold and silver and all matters of precious materials. When wound up, this invention, through delicate clockwork engineering, would sing the Nightingale's sweet melody over and over again. The Emperor was so delighted by this present that he sent the dull, drab, and tired Nightingale away from his palace, and wound the mechanical nightingale repeatedly. Though the original Nightingale and the Emperor would eventually be reunited, the story of the mechanical one is key here.

This artifact inspired the Disney animated version of "Cinderella".

Effects
This extremely delicate device, when activated, sings a melody so sweet that it can hypnotize others into a suggestive trance that lasts for as long as the song plays. However, listening to it causes the victims to be addicted to the notes, and without proper control over this urge will grow sickly and die if not exposed to the song. The owner also grows in greed due to this power, and will often manipulate the bird's abilities towards acquiring large amounts of wealth.

There is a rumor that floating around the Indian subcontinent that there is a feather from the original Nightingale that can reverse the Japanese Nightingale's effects, but no concrete leads have been found on it.