Gigantion

Gigalonia is the name given to the Giant Planet in Transformers: Galaxy Force, the Japanese version of Transformers: Cybertron. It is home to one of four Cyber Planet Keys and ancient Transformer colonies sent to retrieve them. Once part of a star system within the Milky Way galaxy, the planet fell into a spatial rift and was transported to a distant galaxy. The only Transformers to escape its fate were a quartet of Mini-Cons that accidentally got lost in space during a hide-and-seek game with their normal-sized companions. Vector Prime eventually discovered and saved them. Each Transformer on Gigalonia has a Minicon partner, and all of them have construction vehicles as their alternate forms. It's de facto leader is Metroplex. Though claimed by Jolt to be normal sized, the trans-galaxy trip taken by the Gigalonian Transformers seems to have forced them to evolve to sizes ranging from gestalt to Fortress Maximus height. Due to an unknown (as of yet) incident in its past, the Gigalonian Transformers have an obsessive habit of building giant cities and abandoning them, with older cities (the oldest of which are buried deep within the planet's crust) forbidden by law. The planet seems to have a connection to the mysterious Planet X and its inhabitants, Sideways and Soundwave.