The Melody Key is a dream key object that was hidden in the castle of Maryland. It was now owned by Kuromi after she and Baku stole it. Kuromi uses this key to open the people's dream. It has different functions in every seasons, except in Season One and Two. This key was also seen in Kirara.
The Melody Key is a key with gold with black jewel.
Throughout the series, the Melody Key has different functions. In the 1st and 2nd seasons, it opens the people's dreams. In the 3rd seasons, the Dark Version of the Melody Key was obtained which means Kuromi can veil that Melody Key on her partner Baku, turning him into what ever she imagines. Its magic can be reversed using the Melody Takt.
- It is one of the things Kuromi stole.