He is a member of the Evil Horde, he is a robot composed of multiple body parts which he can reform at will into thousands of different shapes. He is a robot equivalent of the character Modulok whose action figure also consisted of numerous different body parts which could be locked together in many different ways. He was marketed as the 'evil robot of a thousand bodies'.
Multi-Bot was packaged with the mini-comic "The Menace of Multi-Bot", which introduces him as a creation of Modulok, whose shape-changing abilities are used to confuse his opponent. His appearance in the mini-comic is significantly different from that of the toy, because the mini-comic was drawn while the character was still in development, and thus he was given his prototype appearance.
As in the mini-comic, he is showcased as a creation of Modulok, although as is the case with Modulok, he was a challenge for Filmation's animators with their limited budget, unable to afford to produce multiple animation cels to represent numerous different shapes. Therefore, like Modulok, he was given one general shape for the show, but whereas Modulok's shape-changing abilities are only ever alluded to in the series ("Happy Birthday Roboto"), the animators were more adventurous with Multi-Bot and show him moving his body parts around in the episode "Black Snow", which involves a comical scene featuring him sticking his heads on upside down. The episode also adds a new dimension to his shape-changing abilities by showing him transforming into a tank-like vehicle in a fashion reminiscent of the Transformers.
The general portrayal of the character is comical. Whereas Modulok is a highly intelligent inventor, Multi-Bot is merely an incompetent robot who serves as Modulok's bumbling assistant throughout the episode, blowing Modulok's cover by accidentally telling She-Ra the whereabouts of Modulok's hideout. Aside from "Black Snow" he also makes a brief cameo in the episode "Horde Prime Takes a Holiday". Due to episodes being broadcast in production order, rather than following the internal chronology of the series, Multi-Bot appears before his creator, Modulok does.