The core set of Autobot Headmasters were vehicles that turned into robots with human-sized pilots that turned into the robots' head. Chromedome turned into a Cybertronic sports car, and his driver, Stylor (see inset) turned into his head. Once the head is plugged in, you can fold down Chromedome's chest plate to get a readout of some of his "Tech Spec" stats. Chromedome was available in 1987.
The combined form of the Universe Micromaster Aerialbots is Superion, an amalgamation of six robots plus their pack-in accessories that serve as connectors, head, and extremities of the gestalt warrior. While in Japan, the original source of the design ( Sixwing , 1992) was available in a collected set, this combiner needed to be purchased one bot at a time in the 2007 Universe release.
