While preparing for Easter, Mickey and friends receive a mysterious machine which, when powered on, begins to generate mysterious egg-rabbit beings - the Usatama, who quickly begin causing chaos.
Behind the scenes
Birth of the Usatama was released in April of 2016, presumably as part of a pamphlet given to guests at Tokyo Disneyland. It was intended to explain the backstory of the park's Easter event. The story was later re-released on the official Tokyo Disneyland website.