To unlock Super Bandage you have to create a level 4 Super Meat Boy. To do this you must defeat Famine, Pestilence, War and Death all in one playthrough, there is however a bug with this item so it will also accept Headless Horseman and Conquest to unlock it even though neither drops the Cube of Meat item.
The easiest way to fight all four in one playthrough is to find the Book of Revelations item before you finish the Basement/Cellar chapter, using the Book of Revelations on a floor gives you an almost guaranteed chance at fighting one of the four horseman as the boss for that floor (Horseman cannot replace Mom/Mom's Heart/It Lives and must be used on the first floor of Depths/Womb)