Multiversal singularity
Across the multiverse, there are many versions of many beings, each existing independently of each other. They may share similarities, or they may be complete opposites, but each is their own unique individual. However, there are a handful of beings of which there is only one, a single entity without a counterpart in the multiverse. Traditionally of great significance, these beings may exist in a number of or all universes simultaneously or they may have the ability to move from universe to universe at will.
Recently though (as of the IDW comics and the live action movies), this conceptual retcon has more or less been flatly ignored, most likely because it's reeaaally contrived. Is Michael Bay daring to take on the cherished canon of some comics a guy wrote for a convention? Only time will tell.
