Once again the Cosmos is thrown into chaos when the King of All Cosmos suffers amnesia after getting hit on the head. In an effort to maintain order, the cousins built RoboKing, a robotic replica of the King. However, RoboKing goes out-of-control and destroys all of the stars in the Cosmos. Once again, it falls on the Prince to roll up objects to restore Cosmos to its glory.
The Prince returns along with a mix of new (RoboKing) levels and old (black and white versions of levels from previous Katamari games) to roll up a wide assortment of objects large and small. New to the series is the ability to make the Katamari "hop" by quickly lifting the controller. In addition to completing levels with size and time goals, there is a large cast of cousins and presents to obtain along the way. The characteristic quirky soundtrack also returns with new songs to enhance the experience.
Katamari Forever was released in 2009 for the PlayStation 3.