Chao Key

The Chao Key is an item that appeared in Sonic Adventure 2 and Sonic Adventure 2: Battle.

Use
Chao Keys are crucial to entering Chao World, as the player will need to collect one as each character and take it to the end of the stage to unlock every character to play as in Chao World.

Appearance
The Chao Key resembles a normal key, albeit blue and the top resembles a neutral Chao head, complete with a yellow ball. In the center of the "head" is a small image of a normal Neutral Chao's face.