An Arbitraryverse is a type of verse that has attributes using undefined/no measurements or an undefined value, or undefined properties/attributes. For example, saying that a verse's size is 10 Gabooglebooglemeters makes that verse an Arbitraryverse due to a Gabooglebooglemeter not being defined. Once that measurement IS defined, that verse will no longer be an Arbitraryverse unless it has other attributes that make it an Arbitraryverse.
Arbitraryverses can spawn in many, MANY paradoxes due to the very wide range of attributes a verse can have. Due to an Arbitraryverse's undefined attributes, they can be really ANYTHING if you say so. This allows for conflicting definitions, something which can completely mess up the verse. This makes it so that only entities that disobey logic can create these verses.