Metroplex is a smaller sub-section of Autobot City, capable of transforming into a battle station or a giant robot comparable in size only with Trypticon (or, later, Fortress Maximus). Metroplex has three smaller autonomous components: Six-Gun: an Autobot who is formed from six of the battle station's guns combining with one of the city's towers, Scamper: an Autobot who transforms into a car, and Slammer: a tank which transforms into another of the city's skyscrapers.
Metroplex is the living core of Autobot City in the year 2005. He is the largest and most powerful of all the Transformers, and is considered the Autobots' last line of defense. He spends most of his time in city mode but has the ability to transform into a battle station or a colossal robot depending on the situation. He is rivaled in size only by Trypticon, and has been called upon to fight the Decepticon on a few different occasions, often using full-body wrestling tactics rather than depending on firepower.
You can check out more on this huge transformers
http://en.wikipedia.org/wiki/Metropl...ransformers%29 and there is transforming picture of his as well.