Professor Paradox explained the multiverse is like a tree. The trunk is the prime timeline, then it has infinite branches, which are the other timelines (Whereas in that timeline something has been changed). Even the slightest thing could've been different in the universe. Such as the word "school" being spelled like "skool".
According toEon, theGhost Zoneis the most strange dimension in the multiverse, that "plays by a different set of rules