Master Shake is a cool, mean-spirited, near-sadistic and self-centered milkshake, in the form of a white cup with a pink straw and two yellow gloves with green stuff in his guts which is probably his blood. Shake's role is to make wild and illogical decisions, presumptions, and demands. He also considers himself to be the group's leader.
A lot of the series' humor is based on the thoughtless abuses inflicted by Shake. Oblivious to any suffering his behavior causes, he will become violently petulant the moment he feels he has been wronged in the slightest. He is utterly incapable of learning anything from even the most catastrophic consequences of his actions. Master Shake is rarely productive and can often be found watching television or, more characteristically, destroying the television and demanding a new one. Shake's usual victim is the relatively passive and generally clueless Meatwad. Shake often causes trouble for their neighbor Carl as well, usually as a side effect of one of Shake's ill-conceived plans. However, Carl and Shake get along somewhat due to the fact that they are both willing to try any seemingly crazy idea (usually for personal gain).
Complementing Shake's laziness is his lack of any overwhelming superpower: when he tries to summon a power, he usually ends up dripping a glob of milkshake or occasionally launching household items from his straw. It is also arguable that Shake has a useless ability to cause any object he holds in his hands to explode simply by dropping it on the ground.
Shake dies or is maimed somewhat frequently as a result of his plans backfiring on him.