Each Key can be used to store Data and in game, as well as unlock new stages/worlds, and various bonuses, and they can be used to connect to the games database to see which keys and Sparkling Aura they have so far.
To use a Shiny Key, the player must insert the key into the key hole built into the machine.
Each key is in the shape of a normal key, but with the head shaped like Mickey's head and themed after the character it is based on. In the keys "teeth" is an icon associated with the character. In the center is a shiny sticker with the character on it, resting behind a clear dome.
The keys come in various colors and come in two pieces that can be combined or separate, with a strap attached to the top half.
There are also special variations of keys, including those made from gold or rose gold, with gem flecks filling the dome on each ear, along with a tiny gem hidden mickey on the left ear. The inside of the center dome has a shiny or glittery background with the character made out of plastic, rather than an applicated sticker.
Introduced in Wave 4 are the Shiny Star Story keys, which are made to resemble a pearl key with a fancier, ornate image in the middle and a gem residing somewehre on the key to match the character, along with the designs on the ear and teeth area.