Hyperion was a planet, the homeworld of the Mouse Jedi known as Mickey Mouse.
The first time Hyperion was referenced was in 2008, specifically within the Acme character key for the non-canonical character, Jedi Mickey. In the real world, Hyperion is a small satellite orbiting the planet Saturn.
Furthermore, the name is a nod to 2719 Hyperion Avenue, which was the original address in Burbank, California for the Walt Disney Studios during the 1920s and 1930s, the era when Mickey Mouse and many other related characters were conceived. Since then, Disney has utilized the Hyperion name in various ways as a tribute to this former studio location, for example, with their Hyperion Books publishing arm and the Hyperion renderer software.