Unspecified Evidence

Unspecified evidence is an argument supported by the claim that evidence exists, but where such evidence is not presented.

This argument is stated as, "there is a lot of proof, but I can't be bothered to show you" or, "there is so much proof that if it is not obvious to you then you must be willfully ignorant of it."

In itself, withholding the evidence that would support a claim is not a fallacy, but expecting someone to accept that claim based on such unspecified evidence is an appeal to authority.

When they make the claim, and then fail to meet the burden of proof, their claim can be logically dismissed until sufficient evidence is offered up to validate the claim in question.